Beitman - Early 1955 Television Servicing Information - TV-9

Most - e - Needed

EARLY 1955VOLUME TV -9

TelevisionServicing Information

VOLUME TV -9

$PRICE

2AO

THEORY

smaimit...

Compiled by

M. N. BEITMAN

SUPREME PUBLICATIONS

Most -often - Needed

1955VOLUME TV -9

TelevisionServicing Information

1111.

1 u t '0,1211 N, t'71.17

Compiled by

M. N. BEITMAN

Supreme Publications

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION

PREFACE

Practically all early 1955 television sets of all importantmanufacturers are covered in this Volume TV -9 of SupremePublications television service manuals. This service mate-rial was originally prepared by various manufacturers to aidin servicing sets of their make. This material has been editedin part and selected with tne thought of supplying you and otherservicemen with the "most -often -needed" television servicingmaterial at the lowest possible cost.

The list of Contents is given on pages 3 and 4, while adetailed Index by manufacturers and model or chassis numberbegins on page 191. Refer to this list and index to find the TVmaterial you need. A Master INDEX to all SUPREME televi-sion and radio manuals is available at 250, postpaid.

Our sincere thanks and appreciation is extended to everymanufacturer whose products are covered by the material inthis manual and who aided us in the preparation of this book.

M. N. BeitmanDecember 1954Highland Park, Illinois

Copyright 1954, by Supreme Publications.All rights reserved. This book, or partsthereof, must not be reproduced in anyform without permission of the publisher.

2


CONTENTSAdmiral Corporation

Chassis 20A2, 20A2Z, and 20D2, Models C2216AZ, K2216A,T2216A, K2217A, T2217A, F2226, C2236A 5 to 9

Chassis 20X5, -A, -B, -CZ, 20XP5 (list of models 10) 10Chassis 19L2, 19L2Z, 19M2, 19N2Z, 19R2, 19S2, 19T1,

19T1C, 19W1, 19W1A, -B, -C, 19Y1A, 20L2 11 to 22Arvin Industries, Inc.

Chassis "E" -- 383, Models 21-554, -555, -557 . . . 23 to 24Chassis "D" 379 -UHF, 382 -VHF, Models 21-550 to -553 25-26

Capehart-Farnsworth CorporationCX-37 Series, Chassis CT -89, CT -90, etc. 27 to 30

(See page 27 for a complete list of chassis and models)CBS -Columbia

Chassis 921-11, 921-13, 921-14, Models U22C05, U22C07,22C09, -B, U22T09, -B, -EB, 22T19, -B, U22T19 31to 34

Crosley Corp.Chassis 426 and 431 (for list of models see page 35). . 35 to 42

Allen B. Du Mont Laboratories, Inc.RA -312, RA -313 Chassis 43 to 46

Emerson Radio and Phonograph Corp.Chassis 120179B, 120203B, 120204B, 120205B, used in

Models 748B, -C, 777B, 787A, -B, 796C, 797B, -C,and 798B, complete servicing information on pages 47 to 56

General Electric Co."F" Series Chassis (for list of models see page 57) . . 57 to 62"G", "J", and "K" Line sets (list of models on page 63) 63 to 68

The Hallicrafters, Inc.Chassis A1600D, B1600D, Models 17T310B, -M, -W,

21T320B, -M,-W, 21K330B, -M 69 to 72Majestic Radio and Television Corp.

Chassis Series 123, 124, 124-2, Models 78, 78A, 79,81, 82, 83, 84, 85, 86, and 88 73 to 76

Montgomery Ward & Co.Models WG-3071E, -F, WG-3073E, -F, WG-3075D, -E,

WG-3077D, -E, WG-3079D, -E 77-78

Motorola, Inc.Chassis TS -525, TS -528, and TS -603 Series 79 to 84

(For chassis types and model numbers see page 79)Chassis TS -418 and TS -518 (for types and models see 85) 85-88

Olympic Radio & Television, Inc.Chassis R, S, U, Models 17CR20, 17TR10, 17TR19, 21CS12,

21CS18, 21CU15, 21CU16, 21KS22, 21TS11, 21TS17 89-92Packard -Bell Co.

Chassis Type 2740 and 2940-1, Models 2742, 2743, 2744,2941, 2842, 2843, 2844, and 3041 93 to 96

3

MOST -OFTEN -NEEDED 195 5 TELEVISION SERVICING INFORMATION

Philco Corp.List of models of "CII line receivers (also data on D-182) 97

TV -300 and TV -301 Chassis 98 to 106TV -350 and TV -354 Chassis 107 to 114

R. C. A. VictorModels 24S529(U), 24S531(U), 24S532(U) using Chassis 115-120

KCS84F, KCS84H, KCS84J, or KCS84K, andModels 24T420(U), 24T435(U) using Chassis KCS84C, -E

Models 17S450(U), 17S451(U), 17S453(U), using ChassisKCS87(A); Models 21S348K(U), 21S355K(U), 21S357K(U),21S362K(U), 21S367K(U), 21S369K(U), using ChassisKCS88, -A, -F, or -H; Models 21S501(U) to 21S506(U),21S517(U) to 21S519(U), 21S521(U) to 21S526(U).21S537(U), 21S5251(U), 21S5252(U), using ChassisKCS88B, -C, D, E, J, K, L, M, V, or VA; Models21S548(U) using Chassis KCS88N or KCS88P. . 121 to 128

Raytheon Manufacturing Co.17T18 and 21T19 Chassis (For list of models see 130)

Sears, Roebuck & Co.Chassis 528.271, 528.292, 528.300, 528.303 . 133 to 136

Sentinel Radio Corp.Models 1U-701, 1U-711, 1U-714, 1U-721, 1U-724, 1U-752,

1U-755, 1U-758, 1U-762, 1U-765, 1U-768, 1U-791 137-142Models 1U-901, 1U-911, 1U-914, 1U-921, 1U-924, 1U-991 143

Sparks-Withington Co. (Sparton)Models 11T210, 12A204, 12A210, and 14A204 . 147 to 149

Standard Coil VHF -UHF Tuner 150

Stewart -Warner ElectricModels 17T -9620A, -B, 21C -9630A, -AB, -C, -CB, -D 151-153Models 21C -9700R, -RB, -W, -WB, -X, -XB . . . 154 to 156

Stromberg-Carlson Company21T and 22T Series Receivers 157 to 160

129 to 132

Sylvania Electric Products, Inc.Chassis 1-522-1, -2, Models 596 Series 161 to 166

Trav-ler Radio Corp.Chassis Nos. 47A3, 48A3, 48A4, 48C4, 49A4 . 167 to 170

Westinghouse Electric Corp.Chassis V-2313, V-2314, V-2323, V-2324 171 to 178

(For list of models see page 171)Zenith Radio Corp.

Chassis 19M20(Z), 19M21(Z), 20M20(Z), 20M21(Z) and19R20, 19R21, 19R22, 22R20, 22R21 179 to 190(For a complete list of models see page 179)

Index 191-192

4


Admiral 20A2, 20A2Z, and 20D2 CHASSISModels C2216AZ, K2216A, T2216A, K2217A, T2217A, F2226, C2236A

(Alignment material on pages 6 and 7; Circuit on pages 8 and 9)

CHASSIS NOTES

The 20A2 and 20A2Z chassis employ the same basiccircuitry with the exception that the 20A2Z chassis has thealuminized picture tube.

The 20A2 and 20A2Z chassis are used in TV only re-ceivers while the 20D2 chassis, with a built-in two tube(AM) tuner, is used in combination models.

HORIZONTAL OSCILLATOR & DRIVE ADJ.

If the Horizontal Drive control (on rear of set) is notproperly adjusted, it may be difficult to obtain sufficientpicture width and brightness.

When switching channels, the Horizontal control (onfront panel) should keep the picture in horizontal syncthrough at least three fourths of its range. If the picturedoes not remain in horizontal sync, then adjust the rearpanel controls as follows:a. Allow the receiver to warm up for a few minutes. Tune

in a station, set the Brightness control at a lower thanaverage setting. Turn Contrast control fully to the left.Important: Before proceeding, be sure that the DXRange Finder control (AGC) is adjusted according tothe instructions given in this manual

b. Turn the Horizontal control (front panel) completelyto the left. Turn the Horiz. Drive control fully to theright.

c. Turn the Horiz. Lock adjustment to the right until thepicture falls out of sync. If the picture cannot be madeto fall out of sync, momentarily interrupt the signal byswitching the Channel control off channel and thenback on.

d. With the picture out of sync, turn the Horiz. Lockadjustment slowly to the left until the picture just fallsin sync.

e. Turn the Channel con-trol to an unused chan-nel. If a white verticalline(s) appears nearthe center of the screen,slowly turn the Horiz.Drive control to theleft until the line(s)just disappears.

f. If, in step "e", theHoriz. Drive controlrequired readjustment, tune in a station and repeat steps"c" and "d" to be sure of proper Horizontal Oscillatoradjustment.

Vertical Line;Adjust HORIZ. DRIVE.

g. Adjustment should now be satisfactory. However, checkadjustment by slowlyrotating the Horizon-tal control in eitherdirection while inter-rupting the televisionsignal by switching theChannel control offchannel and then backon. The picture shouldautomatically fall insync through at least

ofhalf of the range of theHorizontal control. If necessary, repeat the

Horiz. Sync.

above step.

TOUCH-UP OF RATIO DETECTOR SECONDARYUSING TELEVISION SIGNAL (A8, BOTTOM

SLUG OF T201)

Proceed as follows:a. Turn set on and allow about 15 minutes for warm up.b. Tune set for normal picture and sound.c. Carefully insert a non-metallic alignment tool through

the opening in T201. An alignment tool with a screw-driver blade or hexagonal end is required dependingon the transformer used, see * note below. When thealignment tool engages the bottom tuning slug A8, ad-just the slug for best sound with minimum buzz level.Do this carefully as only slight rotation in either direc-tion will generally be required. Correct adjustment pointis located between the two maximum buzz peaks thatwill be noticed when turning the slug back and forthabout 1/4 to 1/2 turn.

d. If necessary, repeat individual channel slug adjustmentand conclude with retouching the ratio detector second.ary. Note: If oscillator adjustment is required for otherchannels, it will not be necessary to repeat the ratiodetector secondary adjustment after once correctly ad-justing it.

ALIGNMENT OF 4.5 MC TRAP A9, USING ATELEVISION SIGNAL

Beat interference (4.5 MC) appears in picture as veryfine vertical or diagonal lines, very close together, havinga "gauze -like" appearance, the pattern will vary with speech,forming a very fine herringbone pattern.

The trap can be tuned by watching the picture and ad-justing the slug A9 for minimum 4.5 MC interference. Ifgreater accuracy is required, the trap should be adjustedas instructed in step 3 under "4.5 MC Sound IF and TrapAlignment" procedure on page7.

If ratio detector transformer (T201) has hollow hexagonal core slugs, bottom slug adjustment Afi can be made from top of chassis, if you usealignment tool (part number 98A30.12; available at Admiral distributor). Bottom slug (A8) can be reached through the hole in the core ofthe upper slug (A6).

Picture Out

5

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION20A2, 20A2Z and 20D2 IMPORTANT ALIGNMENT HINTS

The following suggestions should be performed if difficulty isexperienced during the alignment procedure.1. IF CIRCUIT INSTABILITY: When spot frequency aligningthe IF amplifiers, the VTVM pointer may swing when the hand isplaced too near the IF transformers. When viewing the IF re-sponse curve on an oscilloscope, the curve may change shape withhand capacity, especially when aligning A2 (3rd IF transformerT303). To correct either of these conditions, the following align-ment hints should be tried:

(a) Check the generator output leads to be certain that theunshielded portion (especially the grounded lead) be as short aspracticable.

(b) Be sure that a decoupling network is used at the videodetector output and that the leads on the network are kept asshort as possible (see figure 10).

(c) Construct a special tube shield as shown in figure 7. Thisis made from an ordinary tube shield and four 10,000 ohm re-sistors. Keep the spacing between the two halves of the shieldat a minimum (1/2 inch).

TO TESTPOINT .V

(810Ct0-----AT2ThRF AMP. RF AMP. MIXERI --r

C101 C104 C106

6BC5 6J6OR

A5 23.1 MC MAX. MIXER

A13HF OSC.

ADJ.

PLATE

Figure 9. Top View of TV TunerShowing Adjustment Locations.

10.000 OHMS

CHASSIS

51101010 -

Figure 10. Decoupling Filter.

TO SCOPEOR VTVM310

TYYED

(d) The use of a non-metallic alignment tool, approximatelyeight inches long (part number 98A30-12), will permit adjust-ment without coming too near to the transformers.

TO GENERATORHIGH SIDE

TO GENERATOR

LOW SIDE

23.1 MCA5 MAXMIXER PLATE

Al27.25MC MIN

TRAP

A3V 25.3MC MAX

1ST IF

FOUR

10 K RESISTORSEQUALLY SPACED

- 1/4" GAP

Figure 7. Special Tube Shield forIF Alignment and IF Response Curve Check.

TOP OH SIDE

POINT

1000 OHMS1305

A302

0 0 33 NEC

0

A423.1 MC MAX ' 0

2ND IF1120T 411( MS

-A2 UN 8206

25.3MC MAX 320 OHM 03RD IF

TEST POINTNEG. OF 6205ELEC. 4MFD

TEST POINTJCT. OF C206R206 8 R207

OTEST POINT

JCT. OF L302AND L303

A8 A6 -A7 A9(BOTTOM SLUG) ( TOP SLUG) 4.5 MC MAX 4.5 MC MIN4.5 MC ZERO 4.5 MC MAX SOUND TRAP

RATIO JDET. Pffi. RATIO DE T. TAKEL OFF

Figure 11. Bottom View of Chassis Showing Test Point Connectionsand IF Alignment Data.

IF AMPLIFIER AND TRAP ALIGNMENT Connect bias battery; negative to test point "T", see

figure 11, positive to chassis. A 41/2 volt battery isrequired for all steps below.

Disconnect antenna. Connect a jumper wire acrossthe antenna terminals.

Set Channel Selector to channel 12 or other unassign-

ed high channel, to prevent interference during align-ment.

Set the Contrast control fully to the left (counterclock-

wise). Allow about 15 minutes for receiver and test equip-

ment to warm up. Use lowest DC scale on VTVM.

StepSignal

Gen. Freq.VTVM and Signal

Generator ConnectionsInstructions Adjust

1 *27.25 MC VTVM high side to test point "V" through Connect a 41/2 volt bias battery to test Al for minimum.

2 25.3 MCa decoupling filter; see figs. 10 and 11,common to chassis.

point "T".Use lowest DC scale on VTVM. When peak-

A2 and A3 for maxi -mum.

3 23.1 MC Generator high side to 6J6 (V102) specialtube shield. Connect low side to bottom

ing, keep reducing generator output forVTVM reading of approx. 1 volt or less. A4 and A5 for maxi -

4 *27.25 MC part of the tube shield, see figure 7. If unstable, refer to section 1 of the mum.Repeat step 1 above."Alignment Hints"

5 To insure correct IF alignment, make the "IF Response Curve Check" given below.

Before proceeding, be sure to check the signal generator used in alignment against a crystal calibrator or other frequency standard forabsolute frequency calibration required for this operation.

6

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONIF RESPONSE CURVE CHECK 20A2, 20A2Z and 20D2

Receiver Controlsand Bias Battery G

Sweepor

MarkerGenerator Oscilloscope Instructions

Set Channel Selectoron channel 12 or anunassigned high chan-nel. Contrast controlfully to the left. Con-nect negative of 41/2volt bias battery totest point "T"; posi-tive to chassis.

21.25MC

MARKER

(MAY NOT

BE VISIBLE)

AT LEAST 95%

MEASURED

Connect high side to6J6 mixer-osc. specialtube shield, see fig.7. Connect low sideto bottom part oftube shield. Set sweepfrequency to 23MC,and sweep width ap-proximately 7MC.

If an external markergenerator is used,loosely couple highside to sweep genera-tor lead on tubeshield, low side tochassis. Marker fre-quencies indicated onIF Response Curve.

25.75MCMARKER

50%

-I-A304MAXIMUMDIFFERENCE IN HEIGHT OF PEAKS

SHOULD NOT EXCEED 30'/.

FROM HIGHEST PEAK

Figure 12. Ideal IF Response Curve.

Connect to test point"V" through a de -

coupling filter, seefigs. 10 and 11. Mark-er pips on scope willbe more distinct if a

capacitor from 100mmfd. to 1000 mmfd.is connected acrossthe oscilloscope input.

TOA11-0 If 12 it M Al 2211214LI IKEIR 1211.'ILL 451 CAM 2051E101 02 15.15K 111111

Check curve obtained against ideal re-sponse curve in fig. 12. Note toleranceson curve. Keep marker and sweep out-puts at very minimum to prevent over-loading. A reduction in sweep outputshould reduce response curve amplitudewithout altering the shape of the re-sponse curve. If the curve is not withintolerance or the markers are not in theproper location on the curve, touchupwith IF slugs as instructed below.Important: If curve changes shape withhand capacity, see section 1 of "Align-ment Hints':

25.1'0 MCMARKER

10110 -Of Of M 111 a WILL MAMA, AMYAl ALSO CAKE 10511101 N 22111 41111.

Figure 13. IF Response Curves, Incorrect Shape.

If it is necessary to adjust for approximate equal peaks andmarker location, carefully adjust alignment slugs as instructedunder the above figures. It should not be necessary to turn theslugs more than one turn in either direction.

If the curve cannot be made to resemble the response curveshown at left, repeat all steps under "IF Amplifier and TrapAlignment" making sure that generator frequencies are accurateand adjustments are carefully made. If a satisfactory curve can-not be obtained after repeating these steps, it may be necessaryto change IF amplifier tubes or check for a defective circuitcomponent to be sure that each stage is operating properly.

4.5 MC SOUND IF AND TRAP ALIGNMENTSee page 6' for touch-up of ratio detector using television

signal without test equipment.a. Connect signal generator high side to pin 2 of V304

(6AL5) through a .01 mfd. capacitor, connect lowside to chassis.

b. Allow about 15 minutes for receiver and test equip-ment to warm up.

c. Set Contrast control fully to the left (counterclockwise).

Step

1

2

3

d. Use a non-metallic alignment tool. If Ratio Det.Transformer (T2 0 1) has hollow core slugs, bottom slugadjustment A8 can be made from top of chassis, ifyou use alignment tool, part number 9 8A3 0-1 2 ob-tainable from Admiral distributor.

Signal Gen.Freq. (MC) VTVM Connections Instructions Adjust

When using a signal generator, be sure to check it against a crystal calibrator or other frequency standard for accuratefrequency calibration at 4.5 MC. Accuracy required is within one kilocycle.IMPORTANT: If a signal generator and frequency standard are not available, alignment can be made using a TV stationsignal. Tune in a station and follow step 1, 2 and 3 below. If necessary use a higher scale on the VTVM.

Set to

exactly4.5 MC

High side totest point "Y";

common to chassis.

High side totest point "Z";

common to chassis.


common to chassis.

Use lowest DC scale on VTVM.A6 and A7 for maximum (keep reducinggenerator output to keep VTVM at ap-prox. 1 volt).

Use zero center scale on VTVM, if avail-able.

A8 for zero on VTVM (the correct zeropoint is located between a positive anda negative maximum). If A6 was faroff, repeat step 1.

Connect a 10 mmfd. capacitor from pin7 of V305 (12BY7) to pin 7 of V201(6AU6).Use lowest DC scale on VTVM.

A9 for minimum.

7

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION I

Admiral Corp. Schematic for 20A2, 20A2Z and 20D2 Chassis.

0306 ...-..,

'4T if SUET& v201,---, MICAH. ,---.../ "---'......... y30.r,2 v- saw if 7.--- \

V204...._...,

7---N 20.1F ."---' 5111E0V402 OE TA ACC

511110

\'''''VER(T VsETE1NcT .055°E,,131

OUTPUT

- OUTPU

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V406 15"" VIDEO

0407 .V4.,,03 AMP

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RADIO CHASSIS

CONY. iF.ANP. I

10701 V702 I

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PICT1.11 TIN RA110 DE I V202

v102

RE OSC &NIS! I

V101

AF 11P,

V404

(1 11110115 050

S/1 AMP 2305 FUSE}

HOME syNC. v305 RECTIFIER

0501

NOTE: To read schematic for 20A2and 20A2Z chassis, use sections inheavy solid lines; to read schematicfor 20D2 chassis, use sections in heavydotted lines and connect appropriatepoints indicated by dots coded

61 62 etc.

COLOR DOT

T701-7702

RADIO-PHONOSECTION

20D2 CHASSIS

M703CARTRIDGE

P505000701

5702MO ON -OFF

M705

M706

5701E

TyA DT"TO IC POKI ""

01 1501

Run numbers are rubber stamped at the rear of the chassis.C>,4 0 0 etc. indicate alignment points and alignmentconnections

WAVEFORM DATA(Waveforms given on schematic)

Waveforms taken with Contrast control set fully to the right,all other controls set for normal picture (in sync). DX RangeFinder control set fully to the left (at "0" position). Warning: In-correct adjustment of the DX Range Finder control will causewaveform distortion.

Waveforms at video and sync stages obtained with transmittedsignal input to receiver.

The oscilloscope sweep is adjusted for 30 cycles (which is one-halfof the vertical frequency), or for 7875 cycles (which is one-half ofthe horizontal frequency) so that two pulses appear on the screen.

The peak -to -peak voltage readings shown are subject to some vari-ations due to response of the oscilloscope and parts tolerances.

Waveform at V407 can also be taken by clipping or twisting thelead from the oscilloscope high side over the insulation on the leadconnecting to pin 3. When taking the waveform this way, the shapeof waveform will be the same but the peak -to -peak voltage will bemuch lower, depending upon the degree of coupling.

TV VOLTAGE DATAContrast control turned fully clockwise. Channel Selector seton an unused channel. Other front controls set at approximatelyhalf rotation. Veil. Lin. and Height set at approximately halfrotation. DX Range Finder control set fully to the left (at "0"position).

Antenna disconnected from set with terminals shorted.

Line voltage 117 volts AC.

Voltages measured with a vacuum -tube voltmeter between tube

socket terminals and chassis, unless otherwise indicated.

Voltages at V101 and V102 (VHF Tuner) are measured with tube

in socket. Use an adapter or lift tube out of socket just highenough to allow a needle point probe to contact tube pins. Volt-

ages at pins 1 and 8 of V101 (6BZ7) must be taken as describedabove or no voltage reading will be obtained.

Voltages at V306 measured from top of socket with tube removed.

Voltages marked with an asterisk (*) will vary widely with con-trol setting. In combination models, B+ voltages in TV chassiswill be slightly higher when set is switched to radio position.Alternate voltage readings for radio and TV are shown for soundoutput tube V204 (6Y6G) in 20D2 chassis.

CAUTION

Pulsed high voltages are present on the cap of V405, pin 3 of V407and on the filament terminals and cap of the 1B3GT tube. NOATTEMPT SHOULD BE MADE TO TAKE MEASUREMENTSFROM THESE POINTS WITHOUT SUITABLE TEST EQUIP-MENT.

Picture tube 2nd anode voltage can be measured from the 2ndanode connector and should be taken only.with a high voltage instru-

ment such as a kilovoltmeter or a vacuum -tube voltmeter with a Figure 21.high voltage probe. 2nd anode voltage is approximately 163 KV.

TV TUNER 94D46-4

IF ANIv.01

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HILT ARENA

1 570

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2002 CHASSIS

TURRET ALTON SETTING SELECTS PAIR OfCOILS 1.10111102 FOR 011,1411 DOWER

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L307

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8

I MOST -OFTEN -NEEDED 19S S TELEVISION SERVICING INFORMATION

6BE6 6BA60 AMP

v701 /02 /SOT701 7702

C/09100

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70TTED LINE FOR 10/12 1 20121 CHASSIS

201

104

L103MAC0113

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VOLMER2

20A2 & 20A2Z CHASSIS6AV6 6AS5

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V203 /900

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9


20X5, 20X5A, 20X5B,Admiral 20X5CZ, 20XP5AModels T1831, T1832, T1842, T2212B, T2242BZ, C2256, K2256, K2257Since these chassis are very similar to 20A2 series chassis and in somerespects are like the 19 series chassis (pages 5 to 9, and 11 to 22), theimportant differences will be explained below. In servicing these chassisrefer to the similar material as suggested below.

CIRCUIT DIFFERENCES

Below is a brief description of circuit differ-ences between the 20X5 series of chassis, and theprevious 20 tube chassis.

TUNER: The VHF tuner used in VHF only models isnearly the same as that used in the equivalent lateproduction 19 series or 20A2 series chassis. How-ever, the plate voltage of the RF amplifier tubeV101, 6BZ7, has been reduced to minimize failureof the tube.

IF AMPLIFIER: The IF amplifier is essentially thesame as that used in the 19 series chassis, withone important exception. The adjacent channelsound trap, L301, was moved from the plate circuitof the 1st video IF amplifier V301, to the gridcircuit. This results in a more gradual slope ofthe IF response curve on the video carrier side,making the alignment of the 20X5 series chassisless critical than that of either the 19 or 20A2series chassis. Also, the adjustment of the FINETUNING for the best picture is made easier.

VIDEO AMPLIFIER: The screen voltage of the videoamplifier tube, V305, a 6CB6, has been increased,as compared to the 19 series chassis; thus decreas-ing the possibility of picture instability causedby overload of the receiver on very strong signals.The ability to operate on very strong signals isbecoming increasingly important as stations con-tinue to increase their power.

PRINTED CIRCUIT: The 20X5 series chassis utilizesa printed circuit assembly that includes the videodetector and AGC tube, V304; video amplifier, V305;sound IF amplifier, V201; ratio detector, V202;sound amplifier, V203 and sound output, V204. Thecircuit and component values are the same whetherthe printed circuit or conventional wiring is used.Printed circuits offer the advantages of neatnessand uniform quality. The possibility of incorrectwiring or poorly soldered connections is eliminated.The circuits are photo -etched on sensitized copperplates bonded to an insulating base. After allcomponents, such as resistors, transformers andcondensers, are assembled to the plate the latteris dipped briefly in a molten solder pot. Thesolder adheres to the etched circuit.

AGC: Extensive field tests have proven that incor-rect adjustment of the DX RANGE FINDER control usedon previous models often caused picture instability.To prevent this, the AGC circuit of the 20X5 serieschassis has been designed to provide the optimumAGC characteristic for this type of chassis; thus,making an external control unnecessary.

HORIZONTAL SYNC: The sync separator, sync inverter,horizontal sync discriminator, and horizontal oscil-lator circuitry is practically identical to thatused in the 20A2 chassis.

HORIZONTAL DRIVE CONTROL: The HORIZONTAL DRIVE con-trol is a compression type trimmer capacitor usedas a variable reactance in series with the horizon-tal output tube grid circuit. With maximum capac-ity, which is obtained with full clockwise rotationof the control, the horizontal drive will be maxi-mum. In the 19 and 20A2 series chassis, the HORI-ZONTAL DRIVE control was a trimmer capacitor inshunt with the grid of the horizontal output tube.Therefore, the action of the HORIZONTAL DRIVE con-trol in the 20X5 series chassis is opposite tothat of the 19 and 20A2 series chassis.

HORIZONTAL OUTPUT: The use of a new horizontal out-put transformer and the horizontal deflection cir-cuit design, makes the use of HORIZONTAL WIDTH andLINEARITY controls unnecessary. The newly design-ed transformer provides adequate width, even atlow line voltage; with very good linearity. Underabnormally low line voltage conditions, below 105volts AC, the width can be increased by reducingthe value'of the horizontal output tube screengrid decoupling resistor R439, to a minimum of12,000 ohms.

FOCUS: All 20X5 series chassis, use electrostatic-ally focused picture tubes and do not require ex-ternal focus assembly or control. However, thefocus of the picture tube is affected by the posi-tion of the ion trap.

PICTURE TUBES: Since the picture tubes are electro-statically focused and require no external focusassembly or control, a simpler picture tube mount-ing assembly is used. The inherent focus of thesetubes is uniform over the entire viewing area.

ALIGNMENT PROCEDURE

In general, the alignment procedure is the sameas that for the 20A2 series chassis.

With the exception of the location of the ad-jacent channel trap L301, the chassis layout isalmost identical to that of the 20A2 Chassis.

10


Admiral19L2, 19L2Z, 19M2, 19N2Z, 19R2, 19S2, 19T1, 19T1C,

19W1, 19W1A, 19W1B, 19W1C, 19Y1A, and 20L2 CHASSISModels using the above listed chassis are: TA1811, TA1812, TA1822, TA2211,TA2212, CA2215Z, LA2215Z, TA2215, CA2216Z, HA2216Z, KA2216, LA2216Z,TA2216, -A, CA2217Z, HA2217Z, KA2217, LA2217Z, TA2217, -A, TA2218,TA2222, FA2226, KA2226, TA2226, KA2227, CA2236, -A, CA2237, TA2242,CA2246, and CA2526.

The service material below and continued through page 22, with a few exceptionsis applicable to all chassis listed above. The circuit diagram of the 19T1C chassis(with 17" picture tube), 19W1B and 19W1C chassis (with 21" picture tubes) is pub-lished on pages 16-17. These are all -channel receivers. Chassis 19T1, 19W1, and19W1A, also employ the same basic circuitry as do these other sets. The principalelectrical difference is the inclusion of the DX Range Finder control in these addi-tional sets. The partial circuit of 20L2 chassis printed on the next page, over, showsthe wiring of DX Range Finder circuit. These various chassis use one-piece narrowchassis pan as do some of the later production 19W1 sets and others so described.

Chassis 19L2 and 19L2Z (Z means aluminized picture tube) differ in minor res-pects from the other sets and do have DX Range Finder control. These sets as wellas many of the others have tone controls. Chassis 19R2 uses a 24" picture tube anddiffers in a small way from the other sets. For example, 19R2 uses 12BY7 videoamplifier, 6AV5 vertical output, 6CD6G horiz. output, and 6AU4GT damper tube.

Chassis 19M2 is a combination receiver of the same series and has a built-in2 -tube AM radio tuner. The 19N2Z chassis is a combination set having a separate3 -tube AM radio (Model 3D1) with automatic recod changer RC600 combined in oneassembly. These sets, of course, incorporate needed switching arrangement.

The 19Y1A and 19S2 chassis (both using 21" picture tubes) also use the samebasic circuitry corresponding in the main to 19M2 and 19L2. However these newersets omit DX Range Finder and employ one-piece narrow chassis pan. The circuitof 19W1B chassis printed on pages 16-17 may be used for trouble -shooting theseadditional sets. Some minor part values may differ and there is a slight differencein tube location.

Chassis 20L2 uses type 21ZP4A picture tube and type 12BY video amplifier.Some of the voltage values differ from values shown in the circuit on pages 16-17.The sync circuits differ considerably and this portion of the circuit applicable tochassis 20L2 is printed on the next page, over.

In general, alignment information and other service data is applicable to allchassis types described on the pages that follow.

If separate VHF and UHF external antennas areused, connect the VHF antenna lead-in to the lower an-tenna terminals and the UHF antenna lead-in the upperantenna terminals.

TO COMBINATION VHF -UHF ANTENNA

31/4" 11 F 31/4"

SHORTED END

Figure 1. Antenna Connections When CombinationVHF -UHF Antenna is Used.

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MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 19W1A, 19L2, 19L2Z, 19M2, 19N2Z and 1911

SIMPLIFIED ALIGNMENTAfter becoming familiar with alignment procedure, some servicemen simplify subsequentalignment of sets by merely using the essential alignment data given in figures below.

ALIGNMENT TOOLSThe following alignment tools are required. They can be

obtained from the Admiral distributor under the partnumbers listed below:

Metal alignment screwdriver part number 98A30-9.Non-metallic (fiber) alignment screwdriver (111A" long,1/s" diameter) part number 98A30-10.

Non-metallic alignment wrench (9" long, for large hex-agon core IF slugs) part number 98A30-12.

Non-metallic alignment wrench (9" long, for small hex-agon core IF slugs) part number 98A30-14.

INSULATEBOTTOM WITHMASKING TAPE

Figure 29. Tube Shield for IF Alignment andIF Response Curve Check.

GENERATOROUTPUT 500 OHM

260 OHMS

260 OHMS

500 OHMS

TORECEIVERANTENNA

TERMINALS

Figure 30. Illustration of 12 db Att t ion Pad for ViewingOver-all RF-IF Response Curve.

A16VHF OSC.SLUG ADJ.

43.95 MIN}VTRAP

A7

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MIXER AMP AMP

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Figure 31. Top View of TV TunerShowing Adjustment Locations.

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TEST PONT SEC.RATIO DET PRI. RATIO GET. TARE OFF

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Figure 32. Bottom View of 19T1, 19W1, and 19W1A ChassisShowing Test Point Connections and IF Alignment Data.

TO TESTPOINT *V'

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Figure 34. Bottom View of 19L2, 19L2Z, 19M2, 19N2Z and19R2 Cke Isis Showing Test Point Connections

and IF Alignment Data.

13

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 19W1A, 19L2, 19L2Z, 19M2, 1 9N2Z and 19R2

IF AMPLIFIER AND TRAP ALIGNMENT Connect bias battery; negative to test point "T", see Set the Contrast control fully to the left (counterclock-

figure 32 or 34, positive to chassis. A 4 1/2 volt battery wise).is required for all steps below. Allow about 15 minutes for receiver and test equip-

ment to warm up. Disconnect antenna. Connect a jumper wire across theID Use lowest DC scale on VTVM.antenna terminals.

Note: Since A2 and A3 are adjustments of an over- Set Channel Selector to channel 12 or other unas- coupled double tuned circuit, adjustment of A3 is first

signed high channel, to prevent interference during made at 43.3 MC (step 3) and then at 45.3 MC (step 5),alignment. to obtain proper peak.

Step SignalGen. Freq.

VTVM and SignalGenerator Connections Instructions Adjust

*1 *47.25 MCVTVM high side to test point "V" througha decoupling filter; see figs. 32, 33 and 34,common to chassis.

Generator high side to 6U8 (V102) specialtube shield. Connect low side to chassisnear the tube shield, see figure 29.

Connect a 41/2 volt bias battery to testpoint "T".

Use lowest DC scale on VTVM.When peaking, keep reducing generatoroutput for VTVM reading of approx. 1 voltor less. refer to section 1 ofIf unstable,the "Alignment Hints" on page 1S.

Al for minimum.2 45.3 MC A2 for maximum.3 43.3 MC A3 for maximum.4 45.3 MC Repeat step 2.

5 45.3 MC ReadjustA3 for maximum.

6 45.3 MC A4 for maximum.7 43.3 MC A5 for maximum.8 43.95 MC A6 for maximum.

9 43.95 MCConnect VTVM as above. Generator highside to antenna terminals; full output maybe required.

Follow above instructions. Set Channel se -lector to 2 or other low channel. A7 for minimum.

10 To insure correct alignment, repeat step 1 and 6, then make the "IF Response Curve Check" given below.

* Before proceeding with alignment, turn slugs A2 and A3 out fully (counterclockwise). Check the signal generator used in alignmentagainst a crystal calibrator or other frequency standard for absolute frequency calibration required for this operation.

IF RESPONSE CURVE CHECK(Using sweep generator and oscilloscope)

Receiver Controlsand Bias Battery

SweepGenerator

MarkerGenerator Oscilloscope Instructions

Set Channel Selectoron channel 12 or anunassigned high chan-nel. Contrast controlfully to the left. Con-nect negative of 41/2volt bias battery totest point "T"; posi-tive to chassis.

Connect high side to6U8 mixer-osc. insu-lated tube shield, seefig. 29. Connect lowside to chassis neartube shield. Set sweepfrequency to 44.5 MC,and sweep width ap-proximately 7 MC.

If an external markergenerator is used,loosely couple highside to sweep gener-ator lead on tubeshield, low side tochassis. Marker fre-quencies indicated onIF Response Curve.

Connect to test point"V" through a de -

coupling filter, see

figs. 32, 33 and 34.Marker pips on scopewill be more distinctif a capacitor from100 mmfd. to 1000mmfd. is connectedacross the oscilloscopeinput.

42 MC MARKER

45 75 MCMARKER

45.75 MCMARKER

Figure 35. IF Response Curves, Incorrect Shape.If it is necessary to adjust for approximate equal peaks and

correct marker location, carefully adjust slug A2 and if necessary,adjust slug A3. It should not be necessary to turn the slugsmore than one turn in either direction.

If the curve cannot be made to resemble the response curveshown at right, repeat all steps under "IF Amplifier and TrapAlignment" making sure that generator frequencies are accurateand adjustments are carefully made. If a satisfactory curve can-not be obtained after repeating these steps, it may be necessaryto change IF amplifier tubes or check for a defective circuitcomponent to be sure that each stage is operating properly.

41.05MC MARKER(MAT NOT BE VISIBLE)

Check curve obtained against ideal re-sponse curve in fig. 36. Note toler-ances on curve. Keep marker andsweep outputs at very minimum toprevent overloading. A reduction insweep output should reduce responsecurve amplitude without altering theshape of the response curve. If thecurve is not within tolerance or themarkers are not in the proper locationon the curve, touchup with IF slugs asinstructed below.Important: If curve changes shapewith hand capacity, see section 1 of"Alignment Hints."4 5MC -]

42M C MARKER

AT LEAST 26dbOR 95'/.

INAPPROX.

ITdb (85°/.)- - -NEASURt() FROM

APPROX.3MC

4395 MC MARKER

50%

*-30% MAXIMUMDIFFERENCE IN HEIGHT OF PEAKS

SHOULD NOT EXCEED 30%

HIGHEST PEAK

t45.tSMC MARKER

Figure 36. Ideal IF Response Curve.

14

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 1 9W1 A, 19L2, 1 9L2Z, 19M2, 1 9N2Z and 19R2

4.5 MC SOUND IF AND TRAP ALIGNMENTSee below for touch-up of ratio detector using television

signal without test equipment.Connect signal generator high side to pin 2 of V304 Use a non-metallic alignment tool. If Ratio Det.

(6A15) through a .01 mfd. capacitor, connect low Transformer (T201) has hollow core slugs, bottom slug

side to chassis. adjustment A8 can be made from top of chassis, ifAllow about 15 minutes for receiver and test equip- you use alignment tool, part number 98A30-12 ob-

ment to warm up. tainable from Admiral distributor.Set Contrast control fully to the left (counterclockwise).

Step Signal Gen.Freq. (MC)

I VTVM C ,ions 1 Instructions Adjust1

When using a signal generator, be sure to check it against a crystal calibrator or other frequency standard for accuratefrequency calibration at 4.5 MC. Accuracy required is within one kilocycle.

IMPORTANT: If a signal generator and frequency standard are not available, alignment can be made using a TV station

signal. Tune in a station and follow steps 1, 2 and 3 below. If necessary use a higher scale on the VTVM.

1

Set toexactly4.5 MC


common to chassis.Use lowest DC scale on VTVM.

A8 and A9 for maximum (keep reduc-ing generator output to keep VTVM atapprox. 1 volt).

2High side to

test point "Z";common to chassis.

Use zero center scale on VTVM, ifavailable.

A10 for zero on VTVM (the correct zeropoint is located between a positive anda negative maximum). If A8 was faroff, repeat step 1.

3


common to chassis.

*Connect a 10 mmfd. capacitor frompin 5 of V305 (6CB6) to pin 7 of V201(6AU6). Use lowest DC scale on VTVM.

All for minimum.

In 19R2 chassis, connect 10 mmfd. capacitor from pin 7 of V305 (12 BY7) to pin 7 of V201 (6AU6).

TOUCH-UP OF RATIO DETECTOR SECONDARYUSING TELEVISION SIGNAL (MO, BOTTOM

SLUG OF T201)

"Adjustment A10 is accessible through the %" hole(just below T201) in bottom of the cabinet or the chassismounting shelf, located toward the left side facing the rearof the set. See figures 32 and 34. Removal of the chassisis therefore not required. Adjustment need be made onone channel only. Proceed as follows:

a.

b.

c.

Turn set on and allow about 15 minutes for warm up.Tune set for normal picture and sound.Carefully insert a non-metallic alignment tool throughthe opening in cabinet bottom below T201. An align-ment tool with a screwdriver blade or hexagonal end isrequired depending on the transformer used, see " notebelow. When the alignment tool engages the bottomtuning slug A10, adjust the slug for best sound withminimum buzz level. Do this carefully as only slightrotation in either direction will generally be required.Correct adjustment point is located between the twomaximum buzz peaks that will be noticed when turningthe slug back and forth about 1/4 to 1/2 turn.

ALIGNMENT OF 4.5 MC TRAP All, USING ATELEVISION SIGNAL

Beat interference (4.5 MC) appears in picture as veryfine vertical or diagonal lines, very close together., having

a "gauze -like" appearance, the pattern will vary with speech,forming a very fine herringbone pattern.

The trap can be tuned by watching the picture and adjust.ing slug All for minimum 4.5 MC interference. If greateraccuracy is required, the trap should be adjusted as in-structed in step 3 of the "4.5 MC Sound IF and TrapAlignment".

IMPORTANT ALIGNMENT HINTSThe following suggestions should be followed if diffi-

culty is experienced during the alignment procedure.1. IF CIRCUIT INSTABILITY: When spot frequencyaligning the IF amplifiers, the VTVM pointer may swingwhen the hand is placed too near the IF transformers. Whenviewing the IF response curve on an oscilloscope, the curvemay change shape with hand capacity, especially whenaligning A6 (3rd IF transformer T303). To correct eitherof these conditions, the following alignment hints shouldbe tried:

(al Check the generator output leads to be certain thatthe unshielded portion (especially the grounded lead) be asshort as practicable.

(b) Be sure that a decoupling network is used at the videodetector output and that the leads on the network are keptas short as possible (See figure 33).

(c) For injecting IF signal use an insulated tube shieldover V102 (6U8) Oscillator -Mixer tube. Insulate bottominside of tube shield with masking tape; see figure 29.

(d) The use of a non-metallic alignment tool, approxi-mately eight inches long (part number 98A30-12), will per-mit adjustment without coming too near to the transformers.

° Ratio detector transformer T201) has hollow hexagonal core slugs, bottom slug adjustment Alt) can be made from top of chassis, if you usealignment tool (part number 98A30-12; available at Admiral distributor). Bottom slug (A10) can be reached through the hole in the tore ofthe upper slug (A8).

15

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17

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 19W1A, 19L2, 19L2Z, 19M2, 19N2Z and 19R2

VHF TUNER RF AND MIXER ALIGNMENTConnect negative of 41/2 volt bias battery to AGC generator to the antenna terminals. To avoid distor-buss (test point "T"), positive to chassis. If it is diffi- tion of the response curve, keep sweep generatorcult to obtain a curve of sufficient amplitude, remove output at a minimum, marker pips just barely visible.battery and connect a wire jumper from test point Connect oscilloscope to test point "W" on tuner"T" to chassis. (figure 38). Keep scope leads away from chassis.Connect sweep generator (with 300 ohm output) toantenna terminals. If sweep generator does not have Allow about 15 minutes for receiver and test equip -a built-in marker generator, loose y couple a marker ment to warm up.

StepMarker Gen.

Freq. (MC)Sweep Gen.Frequency

Instructions

1

193.25 MC(Video Carrier)

197.75 MC(Sound Carrier)

SweepingChannel 10.

See frequencytable below.

Alternately adjust Al2 and A13 (figure 38) as required to obtain equal peak amplitudes andsymmetry, consistent with flat top appearance, proper band width and correct marker 1=-tion; see figure 37.

2

83.25 MC(Video Carrier)

87.75 MC(Sound Carrier)

SweepingChannel 6.

See frequencytable below.

Adjust 414 as required to obtain curve having maximum amplitude and flat top appearanceconsistent with proper band width and correct marker location; see figure 37. After corn -pleting adjustment, recheck adjustment of step 1.

3

Set the sweep generator to sweepthe channel to be checked. Setthe marker generator for thecorresponding video carrier fre-quency and sound carrier fre-quency.

Check each channel operating in the service area for curve shown below. In general, theadjustment performed in steps 1 and 2 are sufficient to give satisfactory response curves onall channels. However, if reasonable alignment is not obtained on a particular channel, (a)check to see that coils have not been intermixed, or (b) try replacing the pair of coils forthat particular channel, or (c) repeat step 1 for a weak high channel as a compromise ad-justment to favor the particular channel. Repeat step 2 for the weak low channel to favorthe particular low channel. If a compromise adjustment is made, other channels operatingin the service area should be checked to make certain that they have not been appreciablyaffected.

VHF FREQUENCY TABLE

DIP SHOULD NOT

ChannelNumber

ChannelFreq.,MC

VideoCarrier,

MC

SoundCarrier,

MCHF Osc.,

MC

EXCEED 307. OFTOTAL HEIGHT

2 54-60 55.25 59.75 101

3 60.66 61.25 65.75 107Hal-- 4.5NC

4 66.72 67.25 71.75 113

5 76.82 77.25 81.75 123

6 82.88 83.25 87.75 129MARKER, VIDEO CARRIER MARKER, SOUND CARRIER 7 174.180 175.25 179.75 221

8 180.186 181.25 185.75 2279 186.192 187.25 191.75 233

Full skirt of curve will not be visible unless generator 10 192.198 193.25 197.75 239

sweep width extends beyond 12 MC. 11 198.204 199.25 203.75 245

Figure 37. RF Response Curve. 12 204.210 205.25 209.75 251

13 210-216 211.25 215.75 257

416VHF OSCSLUG ADJ.

A74395 MIN.

TRAP

41 A2 Al2 A14VHF 45.3 MC VHF RF VHF RFMIXER MAX AMP AMP

V.

Figure 38. Top of Tuners, Showing VHFAdjustment Locations.

416VHF OSC

SLUG AN

Figure 39. Front View of Tuner.

18

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 19W1A, 19L2, 19L2Z, 19M2, 19N2Z and 19R2

OVER-ALL VHF AND IF RESPONSE CURVE CHECKReceiver Controlsand Bias Battery

SweepGenerator

MarkerGenerator

Oscilloscope Instructions

Contrast control fullyto the left. ChannelSelector on channel10 or other unas-signed high channel.Connect negative of41/2 volt bias batteryto test point "T",positive to chassis.

Connect to antennaterminals. Set gener-ator to sweep VHFchannel selected. See

frequency table onpage 27. Keep gen-erator output as lowas possible, to preventoverloading.

If an external markergenerator is used,loosely couple highside to sweep gener-ator lead. VHF markerfrequencies are shownin frequency table onpage IS.

Connect to point "V"through a decouplingfilter; see figs. 32, 33and 34.

50%

MAXIMUM

DIFFIDENCE IN NEICIIT OF PEAKSSNOW) NOT EXCEED 50.1.

MEASURED FRO* DIDNEST PEAK

SOUND CADDIEDMADDED

OM DOI BEVISIBLE)

AT LEAST 95'4 POINT

Figure 40. Ideal Over-all VHF and IF Response Curve.

Note that video carrier (marker) on the "Over-all RF-IF Re-sponse Curve" will appear onthe opposite side of the curve ascompared to the "IF ResponseCurve" figure 36. This is due toaction of the mixer tube.

Compare the response curve obtainedagainst the ideal curve shown infigure 40. If the curve is not withintolerance, touch up the IF slug as in-structed below. It should never benecessary to turn slugs mare than oneturn in either direction. If the curveis satisfactory on the channel checked,all other channels should also be sat-isfactory.IMPORTANT: When sweep output isreduced, response curve amplitude onscope should also decrease, but curveshape should remain the same. Ifcurve shape changes, reduce sweepoutput and/or the scope gain until theshape does not change.

Curves must have approximate equal peaks and correct marker location. If it is necessary toadjust for approximate equal peaks and marker location, carefully adjust slug A2 and if neces-sary adjust slug A3. It should not be necessary to turn the slugs more than one turn in eitherdirection.

Figure 41. Over-all RF and IF Response Curves, Incorrect Shape.

HORIZONTAL SYNC ADJUSTMENT

A receiver which requires horizontal sync adjust-ment can be corrected only by following in exactdetail the step-by-step procedure given here.

Check whether adjustment is necessary by rotating theHorizontal control (A) on the front panel from one endto the other; the picture should hold as follows:

a. For strong or medium signals, the picture should remainin sync over the entire rotation of the Horizontal con-trol. Horizontal sync adjustment is required if the pic-ture falls out of sync, bends at the top (jitters), ordoubles up on the side. See illustrations at upper right.

b. For weak or fringe area signals, the picture should re-main in sync over 1/, to 3/4 of the rotation of the Hori-zontal control. Horizontal sync adjustment is requiredif the picture falls out of sync, bends at the top (jitters),or doubles up on the side. See illustrations below.

Picture Out of Horiz. Sync. Bending or Jitter at Top.

Make Horizontal Sync Adjustment as follows:

1. Set the DX Range Finder at "0" position (see chassisillustrations) and set the Contrast control (on frontpanel) for normal picture.

2. Important: Before making these adjustments, be surethat the picture can be made to sync vertically (remainstationary up and down) as lack of both vertical andhorizontal sync is an indication of trouble in the synccircuits. If replacement of tubes V303, V401, V4.03 doesnot eliminate sync trouble, check for other trouble in thesync circuits.

19

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 19W1 A, 1912, 19L2Z, 19M2, 19N22 and 19R2

HORIZONTAL CONTROL 0(ON FRONT PANEL)

Oopa

CI

HORIZ.FRED.

ODX RANGE

FINDER

Figure 10. Rear View of Chassis Showing HorizontalSync Adjustments.

3. With the picture in sync, rotate Horizontal control (A)on front panel from one end to the other. If picturedoes not hold sync as described in paragraphs "a" or"b" at left, set the Horizontal control (A) at the pointwhere the picture just loses sync or becomes unstable,and slowly adjust the Horizontal Frequency (B) un-til the picture just falls back into sync. It may requireseveral turns of adjustment I B). Repeat this procedureuntil the picture holds as described in paragraphs "a" or"b" at left. If the picture can be made to hold syncwith adjustment of (B), adjustment is complete.

4. If horizontal sync is still unsatisfactory, carefully repeatentire procedure. Try replacing tube V403. It may benecessary to make Complete Horizontal Oscillator Align-ment (using an oscilloscope).

COMPLETE HORIZONTAL OSCILLATORALIGNMENT

(Requires Oscilloscope)

1. IMPORTANT: Set the DX Range Finder at "0" posi-tion and set the Contrast control (on front panel) fornormal picture.

2. Connect oscilloscope high side through a 10 mmfd.capacitor to terminal marked "C" or "2" on the hori-zontal oscillator transformer T404 (see figure 11). Itis important to use short leads and a very low capacitycapacitor (at least 10 mmfd.) to avoid loading the cir-cuit and thus distorting the waveform.

DXRANGEFINDER

or 2

HORIZ.FRED.

HORIZONTALCONTROL ONFRONT PANEL

C4I801 MFD

10%

HORIZ. LOCK

Figure 11. Bottom View of Chassis Showing HorizontalSync Adjustments.

3. Set the oscilloscope sweep to 15.75 KC or a sub -multipleof it.

PEAKS MUST NAVE EQUAL HEMP

Figure 12. Horizontal Oscillator Waveform.

4. Adjust the Horizontal Lock slug (D) (see figure 11)until the oscilloscope waveform pattern appears as infigure 12. The rounded and pointed peaks of the wave-form must have equal height. The picture must be keptin sync to obtain the proper oscilloscope waveform pat-tern. Keep the picture in sync by adjusting the Hori-zontal Frequency adjustment (B). If the picture stillwill not sync, check for a defective tube, components, orwiring, before continuing further.

5. Disconnect the oscilloscope leads.

6. Set the Horizontal control (A) fully counterclockwiseto break sync. If the picture does not go out of sync,momentarily interrupt the channel selector, or adjustthe Horizontal Frequency ( B ) until several bars ap-pear sloping downward to the left (see figure 13), thenadjust the Horizontal Frequency (B) until the picturefalls back into sync.

Figure 13. Pi Out of Horizontal Sync.

7. Rotate Horizontal control (A) on the front panel fromone end to the other. The picture should hold sync asfollows:

a. For strong or medium signals, the picture shouldremain in sync over the entire rotation of theHorizontal control. If it falls out of sync, bendsat the top (jitters), or doubles up on the side;sync adjustment is required; see step 8 below.

b. For weak or fringe area signals, the picture shouldremain in sync over 1/2 to a of the rotation of theHorizontal control. If it falls out of sync, bendsat the top (jitters), or doubles up on the side; syncadjustment is required; see step 8 below.

8. If picture does not hold sync as described in paragraphs"a" or "b" above, set the Horizontal control (A) atthe point where the picture just loses sync or becomesunstable and adjust the Horizontal Frequency (B)until the picture just falls back into sync. It may re-quire several turns of adjustment (B). Repeat this pro-cedure until the picture holds as described in para-graphs "a" or "b" of step 7.

20


TUNING CONTROL

Components on the underside of the tuner are easily ac-cessible for replacement after removing three or four setsof channel coils. However, resistors R110 (15,000 ohms)and R116 (10,000 ohms) may be difficult to replace, sincethey are located under the stationary contact strip. If re-sistors R110 or R116 require replacement, it is suggestedthat the entire tuner be returned to the Admiral distributorfor replacement.

RESISTOR CHANGED TO INCREASEHORIZONTAL SYNC

Run 6 in Television Only ReceiversResistor R406 was changed from 18,000 ohms, 1/2 watt

to 22,000 ohms, 1/2 watt in all television only receiversstamped Run 6 and higher.

This change was made to increase the amount of hori-zontal sync available at pin 1 of the sync clipper tube(V30313).

SERVICE HINTSTROUBLE SHOOTING

The sound output tube V204 (6Y6G or 6AS5) functionsas a voltage dropping tube in addition to being a soundoutput tube. The cathode of the sound output tube oper-ates at approximately 140 volts above chassis ground forTV operation. If the sound output stage becomes defective,B+ voltage to the TV tuner, sync separator and clipper,video amplifier and AGC delay circuit will be affected.

It is important to note that the plate and screen voltagesat the first and second IF amplifier stages V301 and V302,may vary over a wide range, depending on the strength ofthe TV signal. The voltages shown on the schematics aretaken with the antenna disconnected and antenna terminalsshorted; see Voltage Data on schematic pages.

SPEAKER FIELD

OR FILTER CHOKE

f X0000TO PIN 8

V501

(5040)

Figure 14. Basic B+ Distribution.

19T1, 19W1, 19W1A, 191.2, 19L2Z, 19M2, 19N2Z and 19R2

In the cascode VHF tuner, the triode sections of the RFamplifier (V101) are in series. The cathode of the secondtriode section is operated at approximately 120 volts abovechassis ground. If the tube should become defective or beremoved from the socket, there will be no B+ voltage onthe plate of the first triode section.

B+ DISTRIBUTION IN TELEVISION CHASSIS

Figure 14 illustrates the basic B+ distribution used inthese chassis. Note: There are variations in the B+ cir-cuits of TV and combination models.

SERVICE HINTS FOR HORIZONTAL SYNC

The horizontal oscillator control circuit controls the hori-zontal oscillator by a method called "Pulse Width Modula-tion". This method is so called, because the width of thepulse applied to the grid of the horizontal oscillator controlsection determines the length of time that current flowsthrough this section. The duration of current flow throughthe control section determines the DC control voltage ap-plied to the grid of the horizontal oscillator, thereby con-trolling the frequency.

The waveshape applied to the grid of the horizontal oscil-lator control section is formed by combining a partiallyintegrated pulse from the horizontal oscillator output andthe horizontal sync pulse. If these two pulses combine prop-erly, the waveshape shown in figure 15 will be developedand the horizontal oscillator will be in sync.

With no sync input, the waveform at the horizontal oscil-

Figure 15. Waveform on Grid Pin 1 of V403With Sync Pulse.

Figure 16. Waveform on Grid Pin 1 of V403Without Sync Pulse.

lator control grid should appear as shown in figure 16.Since the horizontal oscillator control voltage is dependentupon a waveshape formed at the horizontal output stages(V404, V405 and V406), a defective component in one ofthese stages may cause sync trouble. If the waveform shownin figure 16 can be obtained, this will indicate proper opera-tion of the horizontal sweep circuit.

When the horizontal oscillator is out of sync, it may bedifficult to observe this waveform (figure 16) on an oscil-loscope due to the presence of out -of -phase sync pulses. Inthis case, remove the sync separator and sync clipper tubeV401. If the waveshape shown in figure 16 is obtained,

21

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION19T1, 19W1, 19W1A, 19L2, 19L2Z, 19M2, 19N2Z and 1982

place the sync and separator tube back into its socket. Then,remove the horizontal oscillator and control tube V403(6SN7GT). Conventional, well -shaped sync pulses shouldappear at control grid (pin 1) of V403.

If there are no sync pulses, or the pulses are of low orvarying amplitude, accompanied with noise, the sync cir-cuits should be checked. However, if the sync pulses arewell -shaped and of constant amplitude, the horizontal oscil-lator may be misaligned. Place V403 back into its socketand make "Complete Horizontal Oscillator Alignment"given on page 20.

If it is impossible to sync the picture, or obtain the cor-rect waveform at terminal "C", check for a defective com-ponent.

HORIZONTAL SYNC INSTABILITY

Horizontal sync instability occurring after the receiverhas been operated for a short period of time, may be dueto change in capacitor C418 (.01 mfd, 4.00 volts, paper,107( ). The slight change in capacity that occurs with tem-perature rise, may be enough to cause the circuit to becomeunstable. To minimize this possible trouble, a capacitor( with negative temperature coefficient) is used for capacitorC418, part number 64A2-16.

If capacitor C418 is suspected as being the cause of hori-zontal sync instability, it should be replaced only with a.01 mfd, 107( , paper capacitor, Admiral part number64A2-16 or Sprague part number 68P8. Important: Afterreplacing capacitor C418, it may be necessary to make"Complete Horizontal Oscillator Alignment" (using an os-cilloscope) as instructed on page 20.

MISCELLANEOUS TROUBLE DUE TOFAULTY TUBES

Faulty tubes cause the majority of receiver troubles. Thelist below contains most common troubles which are gen-erally due to faulty tubes.

a. Poor fringe area reception due to low B plus voltage.Check the 5U4G tube.

b. Poor fringe area reception due to low sensitivity. Checkthe 6BQ7A or 6BZ7 tube in VHF tuner.

c. Picture and sound separated due to IF oscillation. Checkthe 6CB6 and 6U8 tubes in IF amplifier.

d. Picture bending caused by leakage between tube ele-ments. Check 6CB6 tube in IF amplifier.

e. Poor sync stability, usually more noticeable in verticalcircuit. Check 6U8 and 12AU7 tubes (V303 and V401).

f. Washed out picture due to negative grid current. Check6CB6 or 12BY7 tube (V305).

EXCESSIVE SNOW IN PICTURE DUE TOFAULTY TUBES

Excessive snow in the picture can be caused by faultytubes in the receiver. Check receiver as follows:

Short circuit the antenna terminals and turn the Contrastcontrol fully clockwise.

Connect a vacuum tube voltmeter from test point "V" tochassis. Set the channel selector on an unassigned channel.If the voltmeter reading exceeds .6 volt negative, excessivereceiver (tube) noise is indicated. This condition canusually be corrected by tube substitution. Substitute tubesin the following order: Video detector tube V304, RFoscillator tube V102, RF amplifier tube V101 and IF am-plifier tubes V301, V302 and V303.

Corona or arcing in the second anode supply can alsocause a high noise reading at the video detector resultingin excessive snow in weak signal areas.

ELIMINATING RF INTERFERENCE BYALIGNMENT OF 43.95 MC TRAP A7

Antenna trap L103 (adjustment A7, figures 32 and 34)is aligned for minimum response at 43.95 MC, see IF Am-plifier and Trap Alignment on page 24. Trap L103 attenu-ates interfering signals in the 41 MC IF frequency range.The antenna trap should generally never require realign-ment in the field. However, if RF interference is experiencedfrom radio transmitters or other sources at frequencies(harmonics or fundamentals) in the 41 MC range, thetrap may be realigned to minimize the interference. Thetrap must be tuned when the interference appears. If theinterference is intermittent, tuning the trap may be difficult.

To tune trap, use a non-metallic alignment wrench witha 5/16" hexagonal shank, part number 98A30-12. In sometuners a non-metallic alignment screwdriver with a 1/8"wide blade is required. Tune trap by observing the pictureand adjusting slug A7 for minimum of interference. Itshould not be necessary to turn the slug A7 more than afew turns in either direction. IMPORTANT: Do not turnthe slug completely counterclockwise as channel 2 inter-ference may result.

IMPROVING UHF RECEPTION WHEN ONLY ONEOR TWO CHANNELS ARE RECEIVED

If only one or two UHF channels are being received, re-ception can often be improved by adjusting the oscillatortrimmer which is located at the rear of the tuner; trimmerat lower right hand side. This is especially true if theUHF oscillator tube VI (6AF4) has been changed andthe channels are below 55.

Adjust trimmer while observing picture, tune trimmerfor best picture with minimum of snow. Retune receiverand repeat adjustment.

REPAIRING KNOBS WITH METAL RIM

The metal rim of some television or radio tuning knobsmay become loose and slip as the knob is rotated. To repairsuch knobs, merely punch an indentation in the rim of theknob using a center -punch (preferably automatic). As analternative, a soldering iron can be used by applying thetip to the rear edge of the knob in order to flow the plasticinto full contact with the metal rim.

It is recommended that the knobs be repaired ratherthan replaced, since there may be dimensional differencesin some replacement knobs. Changes have been made toknobs of later production receivers to prevent slipping ofthe metal rim.

22


ARVIN INDUSTRIES, INC.

Chassis "E" -- 383Models 21-554, -555, -557

(Circuit diagram on thenext page, over.)

STAGGER TUNED I.F. ALIGNMENT PROCEDURE

I. Set tuner to channel 9-10 or 11.2. Connect variable bias supply to junction R2Il 4 0207. Adjust bias for -2 volts.3. Connect VTVM across R212. Isolate VTVM with 18K resistor. Use -SV scale.4. Connect RF signal generator to mixer tube shield (VII 5./6). Lift mixer tube shield until it is ust ungrounded.S. Good R.F. grounding between TV receiver on test and test equipment is necessary. A metal surface bench top

should be used to insure proper RF grounding. Use isolation transformer between chassis and AC line.

STEP FREQUENCY ADJUSTMENT INSTRUCTIONS

I. 41.25 Mc L20I for min.

42.9 Mc Tuner coil for max. L7 (top of tuner)

3. 45 Mc L202 for max. Recheck steps 2 and 3

4,

5.

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'T201 for max.

T202 for max.

6. 44 Mc T203 for max.

OVERALL SWEEP CHECK

Recheck steps 4, 5 and 6

I. Connect RF signal generator to chassis near V4 for marker generator. Push shield down on mixer tube.2. Connect oscilloscope across R2I2. Isolate oscilloscope lead with 300 p.taf to ground and 18K

resistor in series.3. Increase bias to -2.5 volts4. Connect sweep generator to antenna terminals. Adjust sweep generator L tuner to charimi 10.

To chassis300

150%

11 . 25

40%

ADJUSTMENT INSTRUCTIONS

T202 T202 positions 45.75 markerT201 T201 positions 42.75T203 T203 adjusts tilt of curve

Note: If desired curve cannot be obtained, slight adjustment of tunercoil and L202 may be necessary.

SOUND AND 4.5 MC TRAP ALIGNMENT

I. Tune in available TV station and reduce signal into set until hiss is heard with sound. This can be done byinserting an attenuator in the antenna lead-in or by removing antenna lead-in from the set and stray feedingin signal by placing lead-in in close proximity of the set.

2. Set buns control in the middle of its range. Adjust take off coil (top LION, LIOZ, Quad rature coil (L103)and buss contra/ for cleanest sound and minimum buss. If any adjustment cause hiss to disappear reducesignal into set until hiss reappears and continue with adjustments.

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ARVIN TELEVISION MODELS 21-550, 551, 552, 553

CHASSIS "D" 379 -UHF, "D" 382 -VHFSTAGGER -TUNED I. F. ALIGNMENT PROCEDURE

I. Set tuner to channel 9-10 or 11.2. Pull AGC tube VIO out3. Connect variable bias supply to junction 5304 4 R306. Adjust bias for -2 volts junction 5202 la R205.4. Connect VTVM across 5212. Isolate VTVM with 18K resistor. Use -Sy scale.S. Connect IF signal generator to mixer tube shield (vzo 6X8). Lift mixer tube shield until it isjust ungrounded.6. Good R. T. grounding between TV receiver on test and test equipment is necessary. A metal surface bench top.

should be used to insure proper RF grounding.

STEP FREQUENCY ADJUSTMENT INSTRUCTIONS

1. 39.75 mc Top 1.202 for min.

2 47.25 mc. Top L201 for min. Outer peak

3. 41, 25 mc .. Top T201 for mi.. Outer peak

4. 42.9 mc. Tuner coil for max.

5. 45.2 mc. Bottom T201 for max. Outer peak --recheck steps 4 and 5.

6. 42.1 mc. Top T202 for max. Outer peak

7. 45.7 mc. Top T203 for nu:. Outer peak

8. 44.1 mc. Bottom T204 for max. Recheck mep 6, 7 and 8

OVERALL SWEEP CHECKI. Connect RF signal generator to chassis near V4 for marker generator. Push shield down on mixer .ube.2. Connect oscilloscope across R212. Isolate oscilloscope lead with 300 old to ground and 18K

reitor in series. To clus.... " To sco3. Increase bias to -3.5 volts at junction R202 k 5205.4. Connect sweep generator to antenna terminals. Adjust sweep generator It tuner to channel 10.1300 PO

CURVE ADJUSTMENT INSTRUCTIONS11.25

T203 'T203 positions 45.75 marker5.75 T202 T202 positions 42.25

5042.2 T204 T204 adjust tilt of curve

5 55% Note: If desired curve cannot be obtained, slight adjustment of tunsm42.75 coil and bottom T201 may be necessary.

SOUND AND 4.5 MC TRAP ALIGNMENT

I. Tune in available TV station and reduce signal into set until hiss is heard with sound. This can be done byInserting an attenuator in the antenna lead-in or by removing antenna lead-in from the set and stray feedingin signal by placing lead-in in close proximity of the set.

2. Set buzz control in the middle of its range. Adjust take o f coil (top T205), top and bottom T101, guadraturecoil (L102) and bus: control for cleanest sound and minimum buss_ If any adjustment cause hiss to disappearreduce signal into set until hiss reappears and continue with adjustments.

Note: If difficulty is encountered eith r in reducing signal sufficiently or adjustments being very broad. The.following proceed. may be used.

STEP EQUIPMENT CONNECTION FREQUENCY ADJUSTMENT INSTRUCTIONS

I. Det. Jig Input of Jig topin 2 of V2

Keep lead between ISKresistor and pin 2 e shortas possible

2. VTVM Output of jig Tune in availablechannel

T205 Top (only), TI01(top and bottom) for

3. Remove jig Same Quadratare coil(L102) for max.sound

Set buss control in middleof its range before adjustingL102

4. Same Dona ceatrol fornilainasn buss

Correct adjustment of busscontrol le approa, middleof its range

S. Det. Jig Junction 0321and 5333

Connect VTVM to outputof jig

6. RF signalgenerator

Pin 1 (V7) 4.8 roc Time 4.S ear trapaortas TAOS for min.

*Detector Jig47mpm--*SW-I

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SERIES

(Circuit diagram isprinted on page 30.)

Arvin INDUSTRIES, INC.

UHF Tuner in ExtremeCounterclockwisePosition

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CAPEHART-FARNSWORTH COMPANYA DIVISION OF INTERNATIONAL TELEPHONE & TELEGRAPH CORPORATION

"CX-37" SERIESTELEVISION RECEIVER CHASSIS

CHASSIS IDENTIFICATIONCX-37 Series-(Early Version)

Chassis Number CRT Size RemarksCT75 17" Rect. Described on page 33, in 1953 TelevisionCT77 21" Rect.CT81 21" Rect. Servicing Manual (Supreme Publications).

CX-37 Series-(With Hinged Secondary Control Cover)CT89 17" Rect.CT90 21" Rect.CT115 21" Rect.-AluminizedCT133 21" Rect.-Aluminized Less Audio, used with separate radio chassisCT95 24" or 27" Rect. 90° Deflection-6AV6 and 6AQ5 Audio CircuitCT130 24" Rect. 90° Deflection-6BK5 Audio Circuit

CX-37-1 Series-(With 82 Channel UHF/VHF Tuner andHinged Secondary Control Cover)

CT110 17" Rect.CT108 21" Rect.CT116 21" Rect.-AluminizedCT134 21" Rect.-Aluminized Less Audio, used with separate radio chassisCT112 24" or 27" Rect. 90* Deflection-6AV6 and 6AQ5 Audio CircuitCT131 24" Rect. 90° Deflection-6BK5 Audio Circuit

For alignment information please see pages 33 and 36, in the 1953 Television Manual.

General DescriptionThe Capehart CX-37 Series TV chassis are all basically

the same. These chassis are composed of two sections;the front section referred to as the RF-IF Chassis and therear section, the Deflection Chassis. The RF-IF chassisbolts to the Deflection chassis providing a basic 21 tubechassis including the picture tube and two rectifiers. Thechassis features a tilted IF strip for ease in adjustrhentand replacing of tubes. Complete isolation is obtainedbetween these sections with all connections being madeby a male plug inserted into the receptacle provided onthe deflection chassis.

The front portion of the RF-IF Unit forms a solidmount for the picture tube while the H.V. Section servesas a rear mount for the CRT and Deflection Yoke. TheH.V. Section is a separate unit which is easily removablefrom the chassis for servicing. There are three basicversions of each the CX-37, CX-37R and CX-37-1 TVseries chassis. A chart has been provided which lists thevarious versions as well as the information necessary todetermine the correct chassis. The chassis can be identi-fied by stamping on the chassis rear apron which can beeither "CX-37", "CX-37R" or "CX-37-1".

The latest additions to the Capehart CX-37 and CX-37-1Series Instruments are those employing the "90° Deflec-tion" 24" and 27" Rectangular Picture Tubes. The chassisemployed in these models is similar to the basic chassiswith exception of the deflection circuits which have beenmodified for the 90* deflection angle tubes. The basicchanges in the chassis itself are:

(1) The addition of a second 5U4G Rectifier.(2) Revision of the Horizontal Output and H.V. Rec-

tifier circuit by use of a 6CD6G tube as HorizontalOutput, an improved Horizontal Flyback Trans. andtwo 6AX4GT tubes as Dampers. These changesprovide the additional scan necessary and 20KV ofSecond Anode Voltage.

(3) The use of a 6AV5GT tube as Vertical Output.(4) The addition of an external magnetic (PM) focuser

for use with magnetically focused 24CP4 and 27GP4Picture Tubes.

In addition to these changes the chassis used in higherpriced 24" and 27" models incorporate an improved audiocircuit using a 6AV6 1st audio stage and 6AQ5 audio out-put stage with a continuously variable tone control. 24"models in the lower price bracket use the standard CX-37audio circuit employing the 6BK5 audio output.

Chassis -Model Cross Reference

4C 174MS-1 CT -110 11924.13-1 CT -112

Model Chassis3C21 4M CT -121 12 F274M CT -95

11174MS CT -126 SC2148 CT -121 12F274M-1 CT -112

IT17411S CT -126 5C21.1M-1 CT -12315W214MD- I CT -134

1T174M-1 CT -110 5C2148-1 CT -123

15W21480-1 CT -134

1T17411-1 CT -110 5C214MD CT -115

16T244M CT -95

IT174MS-1 CT -127 5C214MD-1 CT -116

16T244M-1 CT -112

111748S-1 CT -127 71-1214M CT -121

16T244MS CT -130

2T214M- I CT -108 7112148 CT -121

1672.14MS-1 CT -131

2T2148-1 CT -108 711214M-1 CT -123

16124435 CT -130

2T214MD CT -115 7H2148.1 CT -123

16T2448S-1 CT -131

2T214MD-1 CT -116 992 I 4MD CT -115

16T244ES CT -130

27214MS CT -128 9F214MD-1 CT -116

161244ES-1 CT -131

272146S CT -128 9921480 CT -115

2T214MS-1 CT -129 9F2148D- 1 CT -11618W21490-1 CT -134

I9C214M CT -1,432T214BS-1 CT -129 11F244M CT -95

19C214M-1 CT -1444C174M-1 CT -110 11F244M- I CT -112

19C214MD CT -1454C 1 74MD CT -99 1192448 CT -95

19C214MD-1 CT -1464C 174M5 CT -99

MS-Mahogany Floratone BS-Bisque Floratone M-Mahogany B-Bisque

MD-Highly Polished Mahogany BD-Highly Polished Bisque FD-Highly Polished Fruitwood.

27


CAPEHART "CX-37" & "CX-37-1" SERIES TV(17"21" CRT Version)

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28


"CX-37" SERIESTELEVISION RECEIVER CHASSIS

(Continued on Next Page)

VI 0I3F.

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1M11 1,000,000 001151E COLORS REPER TO SOL. COLON Of MEE OR IMMO COLOR 0111 10,0 VIRE

TUNING O. AV ON TOP. PRON MOPS Or 04.63.6. API AIMCATED PROMS 11010910 VP.COM TUNA00 NOAUSTNENT5 AMNAOLE ORNEATN T. A.NE INO.CATEO G. AMMONS POINTING DOWN.

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29

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONCapehart TROUBLE -SHOOTING NOTES ON THEPicture Circuits

No Picture, No Sound, Raster PresentUse oscilloscope to trace video signal. If video is not

present at output of Video Detector check:(A) R -F Tubes V101 and V102 or I -F tubes V201, 202,

203 and 204.(B) Video Detector Crystal (IN64) and associated

components.(C) Voltage Readings on all R -F and I -F tubes.(D) Plate and Screen load resistors and by pass ca-

pacitors in R -F and I -F Stages.If video signal at Video Detector is normal check:(A) Voltage readings on 1st Video Amp. (%6X8)

V205B.(B) Resistors R219, R220, R224, R225 and R226.(C) Peaking Coil L206 for open.

Horizontal Sync-AFC and Sweep Circuits1. Loss of Horizontal Sync:

If Vertical Sync is critical also check:(A) Sync Sep. 6BE6 or 6CS6 (V402) and Phase

Splitter, 12AU7 (V403) tubes.(B) Sync Coupling Capacitors C406 and C408. (Note:

C408 not used in chassis coded "D-3" or later.)(C) Open Resistors R222, R419, R418, R422; R423

or R424.If Vertical Sync is normal check:(A) Open Capacitors, C510 or C506.(B) Open Resistors R505, R502 or R507.

2. "Jittery" Horizontal Sync:Check:(A) Horiz. Phase Det., 12AU7 (V403B) tube.(B) Value of resistors R503, R504 and R508.(C) Capacitor C513 for open.

3. Extreme Horiz. Sweep Distortion (Picture Distorted- Horiz. Sync critical).Check:(A) Horiz. Phase Det. 12AU7 (V403B) and Horiz.

Osc., 12AU7 (V503) tubes for Heater to Ca-thode leakage.

4. Three Overlapping Pictures (Horiz. Osc. frequencytoo high).If adjustment of Horiz. Osc. cannot correct condition,check:(A) Horiz. Osc., 12AU7 (V503) tube by substitution.(B) Capacitor C517 for open.(C) Resistor R515 for open.

5. Tearing at top of Picture.If adjustments of Horiz. Osc., AGC and Pix LockControl do not correct condition, check:(A) Capacitor C515 for open.

6. No Raster - No High Voltage.Use oscilloscope to check waveform at grid (pin 5)of Horiz. Output 6BQ6GT (V504). If waveform isnormal, check:(A) Horiz. Output 6BQ6GT (V504), H. V. Rectifier

1B3GT (V505) and Damper 6W4GT (V506)tubes.

(B) H. V. Circuit fuse (.2 amp.) for open.(C) Horiz. Winding of Defl. Yoke and Horiz. Output

Trans. (T502) for open.(D) Parallel Resistor R522 and Capacitor C523 for

open.(E) 6BQ6GT Screen Load Resistor R519 for open.If waveform at grid (pin 5) of 6BQ6GT (V504) isnot normal, check:(A) Horiz. Osc., 12AU7 (V503) tube.(B) Coupling Capacitor C518 and Resistor R517 for

open.Horiz. Osc. plate load resistors R509 and R514for open.Horiz. Ringing Coil L501 for open. Also checkvalues of other components in Horiz. Osc. circuit.

7. Insufficient Horiz. Sweep.If condition cannot be corrected by adjustment ofHoriz. Drive and Width, check:(A) Horiz. Osc. 12AU7 (V503), Horiz. Output

6BQ6GT (V504) and Damper 6W4GT (V506)tubes.

(B) Voltage readings on Horiz. Osc. 12AU7 andHoriz. Output 6BQ6GT.

(C)

(D)

CX-37 SERIES TV CHASSIS (Continued)(C) Value of Capacitor C524 in Damper circuit, also

capacitors C518, C517 and other components inHoriz. Osc. circuit.

(D) Capacitor C520 for open.8. Insufficient Horiz. Sweep with Foldover on Right Side.

Check:(A) Capacitor C518 for leakage.

9. Horiz. Foldover in Center of Picture.Check:(A) Capacitor C520 for leakage.

10. Trapezoidal Raster-Horiz. Sweep Decreased.Check:(A) Horiz. Winding of Defl. Yoke for partial short.(B) Capacitor C528 (across Mi of yoke winding) for

short.

Vertical Sync and Sweep Circuits1. Loss of Vertical Sync or Critical Hold.

Use oscilloscope to check sync signal at grid (pin 1)of Vertical Osc., 6BF6 (V501). If sync signal is normal,check:(A) Values of capacitors C534, C530, C535, C529, Re-

sistors R540 and R542 and other components inVertical Osc. circuit.

If sync signal is not normal, check:(A) Sync Separator 6BE6 or 6CS6 (V402) and Phase

Splitter '12AU7 (V403A) tubes by substitution.(B) Voltage readings and waveforms in Sync Separ-

ator and Phase Splitter circuits.(C) Integrating Network (PC501).(D) Coupling Capacitors C408 and C537 for open.(E) Resistor R413 for open.

2. Loss of Vertical SweepCheck:(A) Vertical Oscillator 6BF6 (V501) and Vert. Output

6V6 (V502) tubes by substitution. Use oscillo-scope to check waveform at plate (pin 3) of Ver-tical Output, 6V6 (V502). If waveform is normal,check:

(A) Vertical Winding of Deflection Yoke.(B) Vertical Output Transformer T501.(C) Capacitor C541 for short.If waveform is not normal, check:(A) Voltage Reading in Vertical Osc. (V501) and Ver-

tical Output (V502) circuits.(B) Vertical Output Transformer T501 for open

primary.(C) Resistors R527, R529, R531, R532, Capacitors

C603B, C530, C532, C536 for open also check othercomponents in Vertical Osc. circuit.

3. Insufficient Vertical ScanUse oscilloscope to check waveform at plate (pin 3)of Vertical Output, 6V6 (V502). If waveform is normal,check:(A) Vertical Winding of Deflection Yoke for partial

short.(B) Vertical Output Transformer T501 for partial

short.(C) Capacitor, C541 for leak.If waveform is not normal, check:(A) Vertical Osc., 6BF6 (V501) and Vertical Output,

6V6 (V502) tubes by substitution.(B) Voltage readings on V501 and V502.(C) Capacitor C603C for open.(Di Capacitors C529, C530, C532, Resistors R527,

R529, R531, R532 and other components asso-ciated with V501 and V502.

4. Extreme compression of Scan Lines at Bottom withStretching at top.Check:(A) Adjustments of Vert. Hold, Linearity and Height.(B) Capacitor C534 for open.

5. Vertical Fnldover at top-poor Vert. Linearity.Check:(A) Value of Resistor, R535 and Capacitor, C533.

6. Two Pictures Vertically-Linearity Distorted.Adjust Vertical Hold to stop roll, check:(A) Capacitor C529 for leakage.

7. Vertical Scan Reduced with Stretching at Top.Check:(A) Adjustment of Vert. Hold, Linearity and Height.(B) Capacitors C534 and C533 for change in value.

30


ESSI-Ccolurribia.Chassis Models921-11 U22C05, U22C07, U22C07B, U22T09,

U22T09B, U22T09EB921-13 U22T19, U22T19B921-14 22C09. 22C09B. 22T19. 22T19B

The service material on this page and the next three pages is exact for chassislisted above. The additional chassis 921-12 and 921-94, used in models listedbelow, are very similar in most respects to chassis covered. Different tunersare used, and other types of 21" picture tubes may be employed.

Chassis Models921.12 22T09, 22T09B, 22T09EB,

22C07B, 22C07, 22C05

PICTURE TUBE HANDLING'PRECAUTIONS

The picture tube encloses a high vacuum and with the largsurface area of glass involved, the stresses set up, particu-larly at the front rim of the tube, are considerable. An ab-normal handling stress, accidental blow at a highly stressedsurface, or even a scratch on the surface of the tube couldcause it to implode or collapse with destructive violence.

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SCE TUNERTUBE N TRIMMER

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V16

0:: VERT. OUTPUT% ,-r

`_TRANS

"r

0.019/1 HO*01536A...L3 MX 31

T 201POWER TRANSFORMER

0

\SYNC6" ir.lit33-

;a3(29211

06

HIGH VOLTAGE WARNING

VIO.(6506)

VII 6v6GT t 1 6w4OT 1019/NINA OuTPVT NOiDANPER

09164,51Or°

DEFLECTIONYOKE

CENTERING ADJUST.

016

AtI2

Operation of this receiver outside the cabinet or with coversremoved involves a shock hazard from the receiver powersupplies. Work on the receiver should not be attempted byanyone who is not thoroughly familiar with the precautionsnecessary when working on high voltage equipment.

ovv

1302

31


CBS - Columbia Circuit Diagram for Chassis

921-11, 921-13 and 921-1419? 1 F

120Y24e

250V7103

921.11 & 13 TUNERS

NOTES

I. C135 is 180 MMF. part 4t 23004650 in 921-11 & 13 chassis.2. R244. R245, R242 and S47 are used only in 921.11 8 13 chassis.3. R307 is 22K. IW in some chassis.4. Unless otherwise noted:

Capacitors marked less than I are in mid.Capacitors marked more than I ere in rnmf.Capacitors are rated at 600 V.Resistors are in ohms.All resistors ya Walt.DC voltages measured with a VTVM between socket terminalsand ground.

Indicetes scope synced at vertical sweep rate.Indicates scope synced at horizontal sweep rate.

F. 1 T

W;SEE NOTE.1

19144130V IR IW

LANE WATCH GANGED10 VOLUME CONTROL

T201

V36CB6

71044 2MC

V205U4GRECTIFIER

2130VAC

2611

7'11,I.

AL

402

0 11242 Y 7 - 50000 SEI P2FOTE ,. 17.,---, 192020 9470

551,1c '1.2-iw

Cl)l)63 VAL

C1)

E-1 6.% 2600

TRAP41.25,

Ft

V46CB6

7102

120V

R142396

8KClO

f°83

11347Cl2;;V"i c,, 6200V 200V

097

40 54 51.01310

V9 V8 VI2 V2164E5 606 PICA

TullE

0224 VI4 02031500 T121H7

R244 R245 1

4 K47 1

SEE NOTE 2

TUNER 69000191 USED IN 921.14

R229

5%

R2051006

8236

R79756K

551

L201-

Vs6CB6

Sea I.I.

TRAP39.75

, MC.

RI401, :709.05A.

4'09

260VC201940100350V

C p2 V5 V4 c204 0223 V36C96 we. I 1500 11500

V6GALS

I/2 6711_5

1/2 6AL5

V12A/26U8

130V

11303.2V PP WON

8304OOK

K.00, in

32

IMOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONII 11 Nita 5,08 V7

12BH7vIDEO AMR

490111

1.0 396

RII3471

b°2RU22

00v 20070 206-1400

CH4

TOO

100

300 2

L104PEP

3

$,s

05

7{`)0119M 3100 20

11.117

15,

12 V

1TE

PICH Al5000

CONTRASTL108

8/1

V86AU6

RATIO DET DRIVER250v

L106AUDIO

1510E-OPF 1056

4S160_

61231006

0120 0121Ilk IBIS2W 255%

0

CII9.05

11, "I 1

1.111 T4 IT

1100

012468

1-

.z4e,v

L

.005

20-120V RI25PPLSO

V96AL5156710 OET.

T106

-2qir T 5-61

470 "HV

R 26,425276

1/D1000

/4127 -1-C123391( ICOO

0224 0122 0126

470ce

R25600

IT -3/

NT

P101817120 C127 250K5606 1220 VOLUME R134

vo6AuADV,06

VII6V016G TNJ 0121027 ,

09 6 8 . . 4 9

R:i 3'2

ISyP-Z .4MN '.54; ,C00137 02 28?

p4C129

05'30

420K a 1091

8129g 20 C13

25V

'360.SOLND SYSTDA

4.2On

- SPEAKER 031 I SPEAKER 7802

S7660ARD SOLAR/ SISTER

53

PHOM0

708

1WGREEN

C2010201160350V

4 0 60V

1E1 <ROR

1601 SPEAKEROR 51/404 SPEAKER

6V PP

020612

401111.8.1 4 61

6,44;1101

C205 0213/P

4706400v

V13

12K7SYNC SEP

0206 0207390 -.4,270

R20822 Id/

", 84 V

R20922M

19V

30V01 29 PP

1/2 6U 8PHASE SPUTTER

R210 02112211 156

10VPP

0208 0214 0209

221.

90y

01

8216390

02173

26,0

301301

V15

6AL5105 PHASE DET

E)2 IC30 _L..

.0051

128PP

C303

.005

R305 OV

470e)

R306 - C3043.3M T .05

0307276

I W

SEE NOTE 3

50V

2 3 4 V

105VPP

R2113

2706

R312WOK

6,48 V I4A 40-200010HT2c2

2

R 19 0

V i 4 e743C 216 I /1,T

01

R2254700

5°. 6000002025 REG

101290601 Ill

180V5PPR I

I( 226 8.21

la ct

0/1/1'o'IPA IIIgi1511

P30151(

NOR. NOLO

Nor

. 9 V

C306

R3011 68°6.86

R3098K

T5%

C305 50A. LArc/1

3900CONTROL

62V

C307

470

ITS-Il

c%tir

300

C213

taitC2002

02

1GHT 2

P203

WW'5% VERT.R223 LIM.476 RED

0201 01349 1.26114E6 10 MP D

HOLDVERT. 350 V

VI760V6806-GT

NOR OUT

0313

03114706

0309

C30925-250NOR.DRIVE

CONTROL

39 C3/0

7CIT(25VR314156

BLUE =;a9'

81

N

875PP

OWE

V

20°3ALL. OS -

"V% .1711

Isso

I I

001

4600

m08- 8.6

021151/WD350v

vcv!,6..4

YELLOW

Cil4CDOD300

R2295.61(

W

05

11230,(22M

260V

R2

2265232

13011.3

11 SCOn

II

11

1

43 80 PULS

121

C403121566E316.05

214

0315ISO2W

pa/

Pm

.22.4A

IW

921.14 TUNER

V113

IAX2M.V. RECT.

1556v

0315 Rd500 T 2r

R38

8111119MIESS

52-130 v

235116

YELLOW

390061

nY Y

650 V INP

9.4%

V19 -16W4-GT INOR. DAMPER -LI

I 15A.

NDR1ZGNTALLINEARITY

W -A641 L30OL2

COL

40510v

05 T 1 611.

WIDTH E01110EIL1303

L__

FOCUS ADJUSTMENT

V21

TUBE

1212P4A USED IN 921.41

212 P48 USED w 921-136

'TEST SOCKET ITS)'A R. TOP VIEW

NCE&RET 5

0611260 -

SP6R PLATE 7

3 RAW/ OE%

2 SPIV/ a.

11101 DRCONTI

PM FOCUS & CENTERING UNIT

(Alignment information on the next page, over.)

33


Alignment Information for CBS -Columbia Chassis 921-11, etc. (Continued)

IF ALIGNMENT

1-Connect negative of 3V battery to AGC bus (R102,C104. R106 junction near V3 is readily accessible)or to test socket pin 8. positive to chassis.

2-Remove mixer tube shield, connect Signal Generator,to it and replace over mixer tube so shield does notcontact chassis.

3-Connect VTVM lead through a 22K resistor to gridof first video amplifier (Pin 2. V7, 12BH7) or totest socket pin 5 and negative lead to chassis.

4-Turn receiver on and allow it to warm up a fewminutes.

5-Set VTVM on -5 volt range and signal generator to44.2 mc unmodulated.

6-Adjust 4th IF transformer T104 bottom slug formaximum, output, setting signal generator attenuatorto produce no more than a 3 volt reading on theVTVM.

7-Set signal generator to 39.75 mc unmodulated andadjust T104 trap, top slug, for minimum reading onthe VTVM.

8-Set signal generator to 45.6 mc unmodulated andadjust bottom slug of 3rd IF transformer T103, formaximum output as in (6).

9-Set signal generator to 47.25 mc unmodulated andadjust trap T103, top slug for a minimum readingon VTVM.

10-Set signal generator to 42.7 mc unmodulated andadjust bottom slug of T102 for a maximum VTVMreading as in (6).

11-Set signal generator to 41.25 mc unmodulated andadjust trap T102, top slug, for a minimum VTVMreading.

12-Set signal generator to 44.2 mc unmodulated anddetune the tuner IF coil L3. Then adjust the 1st IFcoil. T101 for a maximum VTVM reading as in (6I.

13-Disconnect the signal generator from the tube shield.

14-Connect Sweep Generator to mixer tube shield andan oscilloscope, calibrated for 3 volts peak to peakas reference output level, in place of the VTVM.

15-Loosely couple Marker Generator to input of theSweep Generator.

16-Adjust Sweep Generator dial and attenuator to showan IF response curve not over 3 volts peak to peakon the calibrated oscilloscope screen. (Exceeding thisvalue will give a distorted response curve.)

17-Adjust tuner IF coil L3 and 1st IF coil T101 toobtain the response curve shown below.

USUALLY: To set 45.75 marker, at 505, point adjust tunerIF coil.

To compensate for tilt adjust 1st IF Coil T101.Adjust for maximum bandwith at the 50% point.

VHF TUNER OSCILLATOR

If all channels are not within range of FINE TUNING con-trol, set FINE TUNING in center of its range and adjust slugreached through front of RF tuner unit for adjustment ofeach channel. CAUTION: Do not touch adjustment on top ofRF tuner unit, other than converter plate coil. L14, duringIF alignment.

SOUND ALIGNMENT

1-Connect 4.5 megacycle signal generator to pin 2 of12BH7 (V7) video amplifier, or to test socket pin 5.

2-Connect DC VTVM (negative polarity) to pin 7of 6AL5 (V9) ratio detector, or to test socket pin 6.Connect negative lead to chassis.

3-Adjust signal generator to precisely 4.5 megacycles;adjust output to read approximately 5 volts on VTVM.

4-Adjust L106 and bottom of T106 for maximum de-flection on VTVM. Keep VTVM reading below 10volts at all times.

5-Attach two series -connected 100K (±1%) resistorsacross R126 (Ratio Detector Load Resistor). Con-nect DC VTVM to center -tap of 100K resistors, andconnect ground wire of VTVM to junction of C122and C124 (Audio Take -Off of T106), or to testsocket pin 3.

6-Adjust top of T106 for zero reading on VTVMbetween a plus and a minus peak.

HORIZONTAL OSCILLATOR ALIGNMENT

If the Horizontal Hold control fails to maintain sync, thehorizontal oscillator should be reset. To reset this screw-driver adjustment, set the Horizontal Hold control in thecenter of its range and sync the picture with the horizontalAFC adjustment screw. Check the hold control action onvarious channels and alter the screw adjustment as requiredto provide syncon all channels.

34


CROSLEYCHASSIS 426

(without UHF Converter)

Models: G-17TOMHG- 17TOBHG-17TOWHG-17TOBKH13-17TOWEH

CHASSIS 426(with UHF Converter)

Models: G-17TOMUG-17TOBUG-17TOWU

Chassis 431, used in Models G-21TOBH, G-21TOMH, G-21TOWH, andChassis 431-2, used in Models H-21COBH, H-21COBU, H-21COMH,H-21COMU, H-21COSBH, H-21COSH, H-21COWH, H-21COWU, H-21HCBH,H-21HCBU, H-21HCMU, H-21HCWH, employ 21ATP4 picture tubes, whileChassis 432, used in Models H-17TOBH, H-17TOBU, H-17TOMH, H-17TOWH,H-17TOMU, H-17TOWU, employs a 17AVP4 picture tube. All these setsare similar to Chassis 426. Chassis 443, used in Models H-21HPBHa andH-21HPWHa, Chassis 443-3, used in Models H-21HPBHd and H-21HPWHd,and Chassis 445 are also similar. Aside from minor differences (such asthe use of 25CU6 hor. output tube, added 3AV6 stage on some sets, and theuse of other tuners) these chassis are so similar that the same material willapply to all these sets.

R.F. AND MIXER ALIGNMENTStepNo.

StationSelector Oscilloscope Bias

Signal GeneratorAdjust

1. Chan. #10 High sidethrough a10,000 ohmresistor toTP1 on Tuner.Ground lead toTuner Case.

-1.5volts towhitelead ontuner.

Signal Generator set to195.5 MC., 400 cycle 30%AM modulated. ThroughDummy Antenna to theAntenna lead-in.

C-3 for maximum 400cycle response on scope.Remove signal Generator.

2.

GENERATOR

OUTPUT TERM& SI 50 owns)

_L

rvwv

W°'""

RESISTORSCARBON

150,1

NOTE - Lead length should be kept ban absolute 'menus,by connectn network Orectly to generator terronala

OUTPUT300otrns

TRANSMISSION LIVETO ANTTERM.

DUMMY ANTENNA

Sweep Generator to An-tenna lead-in throughdummy antenna. Set Gen-erator to sweep Channel10 freq. Loosely coupleMarker Generator tosweep output cable. Setmarker to either 21.9 or26.4 mc.

Adjust C5 & C9, to pro-duce a response curvesimilar to R.F. and MixerResponse Curve.

f

2GAMC 21.91IC

DIP SHOULD NOTEXCEED 3db ON 30%OF TOTAL HEIGHT

R. F. & MIXER RESPONSE CURVE

Without disturbing the R.F. grid, R.F. plate, and mixer -grid trimmer, check the response on the otherVHF TV channels by setting the station selector to the desired channel and changing the frequency of thesweep generator to correspond to the channel being checked. The response curve should be essentiallythe same on all channels and the markers should fall in similar positions on the response curve. A slightamount of tilt can be tolerated. The amount of tilt indicated by the relative amplitudes of the responsecurves where the picture and sound I.F. Markers rest should not exceed 30% of the over-all responsecurve amplitude. (Service material continued on the next 7 pages.)

35


CROSLEY Chassis 426 (Continued)

I.F. ALIGNMENTAll lead connections from the signal marker generator and sweep generator must be shielded. Keep exposed ends andground leads as short as possible (about one inch). Always locate the ground lead connections as close as possible to theirrespective "hot" leads in the television receiver chassis. The sweep generator output, signal generator output, and contrastcontrol must be kept low enough to prevent overloading the television receiver circuits.

CAUTION: One side of the chassis is connected to the power line. Therefore, test equipment should not be connected to thereceiver unless an isolation transformer is used between the power line and the receiver. DO NOT GROUNDTHE RECEIVER CHASSIS UNLESS AN ISOLATION TRANSFORMER IS USED.

The front side of the chassis as referred to below means the side opposite the tubes.The rear side of the chassis means the side onWhich the tubes are mounted.

VIDEO I. F. ALIGNMENT (with VTVM)In the I.F. Alignment, limit input of signal generator so that reading on VTVM does not exceed -2 volts.

StepNo.

Connect Sig-nal GeneratorThrough a .01

Capacitor

Signal Gen.Freq. MC.

ConnectVTVM

MiscellaneousConnections and

InstructionsAdjust

1. Test PointNo.2 on Tuner(closest to L9slug adjust-ment).

24.4 mc. Junction ofR118 and C113and chassis.

Connect 3 volt biasbattery negative leadto white lead fromtuner, positive lead tochassis

T101 for maximum indication on meter, limitinput to make peak less than -2 volts D.C. onVTVM.

2. It 22.9 mc. It It L103 (rear slug) for maximum. Use first peakfrom tinnerman clip end of coil.

3. ,, 21.9 mc. r. ,, L103 (front slug) for minimum. Input levelshould be high enough to produce at least .5volts at null on VTVM. Use first null obtainedfrom end of coil form opposite tinnerman clip.

4. Repeat steps 2 and 3.5. 25.5 mc. ,, ,, L102 for maximum.6. ,. 25.1 mc. ,, 19 L101 (front slug) for maximum. Use first peak

from tinnerman clip end of coil.7. It 27.9 mc. It ,, See Note 1.

L101 (rear slug) for minimum deflection onVTVM. Use first null obtained from end ofcoil form opposite tinnerman clip.

8. Repeat step 6 (and 7, if adjacent channel trap is used).9. Test Point

No.1 on Tuner(closest to C21trimmerscrew).

25.1 mc. Connect a 100 ohmresistor in serieswith a 1000 mmf. cap.across L101.

L9 (brass screw) on the Tuner for maximum.

Note 1. This adjustment can be made only on receivers where the Adjacent Channel Trap has been added.

TO CHECK I. F. ALIGNMENT (with scope)Excessive sweep input will overload the circuit and cause distortion in the wave form. Check for possible overload by tem-porarily increasing and decreasing the signal input level and noting any change in the wave form.

Excessive signal from the marker generator will also distort the wave form. Be sure to keep the marker at the minimumusable amplitude.

Sweep Gen.Connected to

Scope Connectedto Bias

Sweep Gen.Set to Remarks

Ungrounded High side of Connect 3 volt Sweep from Provide markers as shown on curve.shield of V2and chassis.

contrast con -trol and chas-sis. Contrastcontrol at mini-

bias batterynegative leadto white leadfrom tuner,

20 to 30megacycles. 21.9 NOW

26.4 MC

mum contrast. positive leadto chassis.

98%

22.9 MG. 60%

t 23.5 MC.

30% 25.1 MC. ii A%

A slight deviationgreat deviationaligned.

___ 10% LiNominal Overall I.F. Response Curve

in response curve is tolerated,is noted, the I.F. stages will have

but if anyto be re-

36



0138

rT 106

V CRT. 8TO[IT RANO

HEIGHT VERT. OSC.LINEARITYVERTICAL

CONTROLVERT. AMPL.

HORIZ. OUTPUT

1108HORIZ.!'

TO GTO u

L106 OAD?./IT.0®LQUAD. COIL

VERT

HOLD

NOR

014 -OFF

VOLUME

CONTEMN

STATIONSELECTOR

FINET

LIMITERDETECTOR&AUDIO

AMPL.

L109

eSOUND1=4 TAGE-OFF

"PL. 4.5 MC.21114 DETECTORAMPL. COUPLING SEA

VIDEO OE T.

L101

elCOUPLING

T105

ALSO OUTTRANS

LI 2

AUDIO OUTPUT

SRIO

0

0139

SRIO

FRONT VIEW OF CHASSIS 426(Tube & Alignment Locations)

T 103

VENT OUTPUT TRIMS

Ri26

C.)PRI OPR NESS

CONTROL

AUDIOOUTPU T.5L6

ROCSRF

AMPL

11153

TUBE LIFE EMMENRENSTOR

125,1 COLD 454sTRIT

VHF 11F TONER

VERT LINCONTROL

VERT OSCOVERT 10411L

121111,

*NEILGCSE

RI44

ONIIT

CONTAIN

MAN1110 IFAMPL

244MC

via COUPLINGOET

DETECTOR

OHOS OANDER

ass

HOR OUTPUT251106

T 106

\NOR FRED

uSTAFC 6NOR 0%

ESN)

VIE AMPL

i.smc

'5"5 AMPL

- 4i,"' 32

,e. T. AP

5SYNC SYNCCLIPPER Mel61.11 im, Kai

CONTROL

REAR VIEW OF CHASSIS 426(Tube & Alignment Locations & Tube Filament Wiring)

R143

VERT.HOLD

R164

HORIZ.HOLD

81201

CONTRAS'

STATIONSELECTOR

FINETUNING

37

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONCROSLEY VHF OSCILLATOR ALIGNMENT (Continued)

OSCILLATOR ALIGNMENT (using scope)

StepNo. Oscilloscope

ChannelSelector

SweepGenerator

MarkerGenerator Adjust

1. High side ofscope to highside of R120contrast control,Low side tochassis. See Note.

Chan. #2 To sweep Channel2 frequencies.Connect Gen. out-put in series withdummy antenna toantenna lead-in.

59.75. SoundI. F. Carrier.

Channel 2 oscillator slug so that marker fallsinto bottom of valley on curve (the pointcorresponding to the 21.9 mc. marker asshown on Nominal Overall I. F. ResponseCurve sketch.) Be sure that the Fine TuningControl is set to the center of its range.

2. Repeat the above procedure for each of the remaining channels, by resetting the sweep generator and the markergenerator to the correct frequencies for each channel that is to be adjusted.

Note: Apply a -3.0 volts negative bias to Junction of C111 and R117 or to white lead from VHF R. F. TuneUse whichever is the most convenient point.

SOUND ALIGNMENTThe 4.5 mc. trap (front of L109) must be aligned first, regardless of which procedure is used for the remainder ofthe alignment (Procedure A or B).

StepNo.

ChannelSet To Adjust Remarks

1. Anyunusedchannel

Connect a crystal controlled 4.5 mc., 400cycle amplitude modulated signal (30%or greater) between pin 8 of V104 andchassis. Connect high side of scopethrough a detector probe to cathode ofpicture tube, low side to chassis. AdjustL109 (rear slug) for minimum 400 cycleindication on scope.

Remove signal generator and scope from the receiver.

PROCEDURE A (with signal from station)

StepNo.

ChannelSet To Adjust Remarks

1. Strongsignal

L106 for maximum sound output. Set Buzz Control (R132)approximately 90° from clock -wise stop.

2. Weaksignal

L111 and L109 (front slug) for maximumsound output.

If the signal in the area is too strong to obtain thesepeaks, remove the antenna from the receiver.

3. Weaksignal

Buzz Control (R132) for minimum noise(hash),

This signal should be weak enough to allow noise (hash)to come through along with the sound.

4. Strongsignal

L106 again for maximum sound output. Limit the volume control setting so that this peak canbe heard.

PROCEDURE B (with alignment equipment)StepNo.

ConnectSignal Gen.


ConnectScope Miscellaneous Instructions Adjust

1. Pin 8 ofV104.

4.5 mc.FM modu-lated400 c.p.s.,25 kc.deviation.

Across second-ary of outputtrans. T105.

Set Buzz Control (R132) toapproximate l y 90° fromclockwise. stop. Set theVolume Control (R135) at alow level.

L106 for maximum 400 cycleindication on scope.

2. ,, ,, It L111 for maximum responsekeeping input signal at a lowlevel (below limiting).

3. II It II ,, L109 (front slug) for maxi-mum response keeping inputsignal at a low level.

4. ., 4.5 MIAM m >du-lated400 c.p.s.

ft Use a high input level onsignal generator.

Buzz Control (R132) for null(minimum 400 c.p.s. ampli-tude on scope).

5. ,, 4.5 MC.FM modu-lated400 c.p.s.,

,,,,

Set the Volume Control(R135) at a low level.

Re -peak L106 for maximum400 cycle indication on scope.

38



HORIZONTAL BLOCKING OSCILLATOR ALIGNMENTTune Receiver to TV signal, adjust contrast control for normal picture below limiting in the Video Amplifier, and proceed asfollows:

StepNo.

Contrast ControlSet For Miscellaneous Adjust

1. Normal Picture Horizontal Hold Control (R164) and Horizontal Frequency Adjust-ment (rear slug of T108) until picture is in sync.

2. ,, Connect scope in series Adjust Horizontal BTO Trap (front slug of T108) to obtain the wave -with 10 mmf. to lug 4 of form shown below. Keep the picture in sync at all times by re -T108. adjusting the Horizontal Hold, Horizontal Frequency and/or Hori-

zontal Lock Trimmer (C142).- -- - -Adjust so that the peak of pulseIs equal or 10% higher thanpeak of sine wave.

3. " Horizontal Hold set fully Adjust Horizontal Frequency (rear slug of T108) by turning out un-clock-wise. til the picture is just out of sync. Then turn the control slowly in

until the picture is just ready to fall into sync (indicated by a wideblack vertical or diagonal horizontal blanking bar).

4. " Horizontal Hold set fully Picture should normally be in sync. Remove the signal by tuningcounter -clockwise. off and then re -tuning to the station. If more than seven bars are

present, adjust the Horizontal Lock Trimmer slightly counter-clockwise until three or four bars appear when the receiver istuned off and then re -tuned to the station (Horizontal Hold Controlstill set fully counter -clockwise). If less than three bars arepresent, adjust the Horizontal Lock Trimmer counter -clockwiseto obtain the three or four bars as described above.

Since the Horizontal Lock Trimmer adjustment affects the hori-zontal frequency, the adjustments of both the Horizontal FrequencyAdjustment and the Horizontal Lock Trimmer must be repeateduntil the conditions outlined in steps 3 and 4 exist simultaneouslyat the extreme positions of the Horizontal Hold control.

Check pull -in range, which should be normally 60° to 120°.5. Weak Picture Set the Horizontal Hold Control so that when the receiver is tuned

off and then re -tuned to the station, the picture returns completelyin sync.

TABLE OF SOCKET VOLTAGESThe following voltages were measured with an electronic voltmeter while the set was operating on 117 volts, 60 cycle a.c.with no signal input, antenna terminals shorted, Station Selector set to channel 3, and the Brightness and Contrast Controls atminimum setting. Electronic voltmeter connected between socket lug and chassis. * = AC. voltages. Voltages may vary de-pending upon the setting of other controls.D. C. current at junction of L108 and C132B, with contrast control in the maximum counter -clockwise position, 190 ma. Withcontrast set at maximum clockwise position, D. C. current at this point is 200 ma.

SYMBOL TYPE PIN 1 PIN 2 PIN 3 PIN 4 PIN 5 PIN 6 PIN 7 PIN 8 PIN 0

V101 6C 136 -0.7 «0.7 50.4 .44.1 .129 +131 0 --- ---V102 6C136 -0.9 .1.0 44.1 37.8 +131 +133 0 ---V103 6148 +1.0 --- +132 37.8 31.5 +135 0 -1.1V104 6AN8 +7.2 -1.1 0031.5 25.2 +240 +230 .1.7 +5.8

V105 6118 +72 +58 25.2 113.9 +58 +0.7 0 -0.5V106 8BN6 +2.2 --- 44.1 37.8 +95 --- +104 ---V107 6SN7GT +12 +64 to +5.0 -83 .21012.60 .6.3

+120

V108 25L6GT .81.7 +250 .265 +145 .56.7 .150 ___

V109 25BQ6 --- *81.7 --- +130 -27 56.7 0 Cap - HighVoltage

V110 12BH7 100 -22 0 18.9 18.9 .470 +100 .120 12.0VIII 12AX4 --- --- +470 --- +260 .81.7 94 ---V112 1X28 --- --- --- N.V.

13KV

V113 17:1P4 .0 --- --- --- +150 (Pin 10) (Pin 11) (Pin 12)+320 .150 .6.3

VI 613C5 --- 0 .44.1 50.4 .125 .125 0 --- ---V2 616 +80 .90 .50.4 56.7 --- -5 0

39


CROSLEY Chassis 426 Circuit Diagram

4708

470K

470UHF TUNER 5

FUNCTION SNITCH

-USED ON vHF UlfMODELS ONLY ToaeXplACLENTEFILOG4

VHFANT 00 470

SEE SCNEP4ATiCON PAGE 18. 0

(NIGH MEI

rimw

R101

470K

C10

--4--K470

R102

470K

P101

06102

470K4NWV71

470

TO % TUNER 13*

INPUT 260V

VHF RF TUNER PART NO.157282SEE SCHEMATIC ON PRECEDING PAGE

R152

7.5

0 0

V1016086

IET PIK. I -F

L101

,,251MC-05 RI..

AAV:::f + -4-, ii-' 15K I CI4

}.L47 R104

TEL.

100

47., . -c15

Jor ,....4 R108

I C20;

1000 _ iew800 WO C103 4700I 001

.= MFD.

t153v

DC CURRENT

f\ 172 MAA 1_108

22v. P -P

r06000 YEL

SR101

039 a4cie,I- 140

MFD.C0101

SW I

12AX4GT 25806VIII V109

R153

25 OHM -COLD V108430HM- HOT

HEATER CURRENT LALLIMITING RESISTOR 25L6GT(TUBE LIFE EXTENDER)

50^ C1328

04

200MFD 0.2v. P -P

R -F TUNER

6.16 6CB6V2 VI

RI54

43

I

6CB6V101

L102253.40

SEE NOTE II-4-0129

10K

Tv°330K

I

T.x.D.

Ta2446

1 I

219NC

6V102G86

UO3 it2M2 PIK I -F

1.14181

6CB6 6108V102 - V103

6BN6V106

1.004MFD

44v. P -P

6A283V104

.0.48

R112 MT

1000

.006FD_L

Rill8

41-171_106

V104BF26.11/48SYNC.

CLIPPER

128H7

4

68

.14-150 I

F.

17V. P -P .05

RI

3911-)22K

0141 36 v P -P

77V P -P

-1- V1058F26U8

SYNC.4MPL.

C442 1109LOC

10-160

6547 GT 17Hp4

0 107 VII3

RI56 R157 RI58

43 43 43 43C256

1- psL,---

TERMNAL Locoions

2 3

4

1108

L3

TIO9

40

I MOST -OFTEN -NEEDED 1985 TELEVISION SERVICING INFORMATION

SCHEMATIC WIRING DIAGRAM CHASSIS 426

R131113K

V106

LIM8ER-DETECTOR

&I WO AWL.

.2.63

RI321000

BUZZCONTROL

.j471/ RI 34

01231

To'MFG

470

L106

CI 251

T5

CI263

RI350= C127 .111V

I(330K Z

MFD.

.0011/FD.

V10825L6GTAU01

OUTPU0T

ka

RI36

RI3756011

470K

,.f...eaav

2603

TOLUE 105

0C128

MFD.

RED

SP 01

/I03AMANI

PIX I- F

2;

TIOI24.mc---

6 glie--- R I 15 3; I- - ; ..wio

RII4100

0109

1005MFD

7- RI 161000

0101001

WD.

R117

GII 6 I MEG

I/PFD

VIO3B26AM8

VID. DET

L104 11112G.

0600'-

cii2

10 T -q,MFD

01141

-11711-5V RP

5.611

01160116

VIDEO WM..Y26AP18

viO4A SOV e-PLIO9 -LOU r

son_

CI 15 33 L112 < cap'7

R1258.2K

I5MFD

R12015 00CONTRAS

TROLTCON

SOV P -P

/1YEL'. 0 YELLOw11 3

RI

RI 2 3 L105 < 27K4.71( a..a

33K

R124NAV5 6K

NFU

RI27100K

3 7

CONTROL

RI 265MEGBRIGHTNESS

PICTURE TUBEV113

426 1 1711P4

70y P -P

6

SEE

NOTE 6

RI41

4.7KSEE NOTE II ci31

I #701 3 kall9I22 K .005.005 701MFD i ton

RI42MMI1000

z50V. P -P

SEE NOTE 10

\\....R16470KSToP

I70K

HORIZ. HOLD

N.

eux 'n06 TELLON

963. P -P

2

RI43 %2!MEG. VI 10AMK VERT.STOP Ku i'21281.17

CONT VERT

CI33

.005 CI34MID.

..115v1 047 1203MFD 1, P

/ 035 1164

=

C143

233

F5956011

1.4 V. P -P R160150K

27K

RI661001(

C146

64 TO 12043

RI67 1

150K18" P -P

8169_ 1811

SEE NOTE 9

a tt2 7MEG.

3 V107AY26SN7GT

710812. AFC.

R161 RI62150K 100K

0144 CI 451

MFD. /OD.25 1.02

821(RI63

T108

37.5"

a 4

C1471( i31 a

220- --111,738-

-131Tr/ MFD

110 V. P -P

V10764gitS747GT

Z 09C.

4

- V I \e."7".,

(See next page,over, for notes.)

0149±

C150

560

R170470K

C136

611

OvERt V

P -P.1 ELLE TIO7

VII0 B0005 Vz12BH7MFD. VERT

OUTPUT

RI45

7tZ..5%4

1.110-T

82011

510EG.IMEG. STOP

HEIGHTCONT.

RI473

7502 014

VERTLIN.

RED

(.0051

20

L107 -A

MED. -7-

SEE NOTE 8RI46

1511

30G38-}FDL20

MFD.

VERT.MELYOKE

4300V I

815039011

R151820K

SEENOTE

5

V10925606

HCRIZ OUTPUT

yap

100 P -P

6 C151

22.R173 05

-._. \MFD

'=

SEE NOTE 7

VIIII2AX4

DAMPER

8171188

.1-714101f

16.

0

(

VI I 21228

H V RECT.4

109

0 13 K V

1 vcas.-0153 8 00 au :_.2154a 0 .T17

/2 L I07B

HCR1ZDEFLYOKE

1

SEE NOTE 12

J..**

1

RED t6L.10K

41

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONCROSLEY Chassis 426 (Continued)

NOTES1. All D.C. voltages measured with an electronic voltmeter connected from socket lug to chassis. Some

voltages are variable depending upon signal input. Voltages shown were measured with a signal volt-age of 850,000 microvolts and with a normal picture on the picture tube and the contrast and bright-ness controls set for 50 volts peak to peak on the cathode (pin 11) of the picture tube. Socket volt-age tolerance 10%. 1

2. Supply voltage, 117 volts, 60 cycle AC.3. K = 1000.4. On all capacitance values in mmf. and all resistance values in ohms unless otherwise noted.5. R171 is a special 2 watt resistor capable of standing overload for limited periods of time. Replace

with part number 156911-3.6. Better focus may be obtained with replacement picture tubes if the electronic focus anode is con-

nected to a point other than +150 volts. Suggested points to try are: chassis ground, +260 volts,+300 (picture tube, pin 10) and +480 volts.

7. R173 was added on some receivers to minimize horizontal overdrive, noticeable by a vertical whiteband slightly left of the center of the raster. Because of individual tube characteristics, overdrivemaybe introduced when the 25BQ6GT tube is replaced in a set that is not provided with R173. In thiscase it will be necessary to correct the overdrive condition by adding a 22 ohm, 10%, 1/2 watt re-sistor, part number 39374-5. Disconnect tube socket, pin 8, from ground and insert the resistor be-tween the pin and the chassis.

8. In some sets R128 is a 12,000 ohm, 10%, 2 watt resistor (part No. 39374-214). In such cases R148is a 18,000 ohm, 10%, 2 watt resistor (part No. 39374-216) or a 22,000 ohm, 10%, 2 watt resistor(part No. 39374-217).

9. In some sets R169 is a 15,000 ohm, 10%, 1/2 watt resistor (part No. 39374-39).10. In some later production sets, Horizontal Hold control R164 has an overall resistance of 145,000

ohms, with a 70,000 ohm stop. This control will be marked with part No. B-157802-1-2 orB-157802-1-3. It is directly interchangeable with the earlier control marked B-157802-1-1, whichhas an overall resistance of 170,000 ohms with a 70,000 ohm stop. It will be noticed, however, thatthe control with the lower overall resistance gives a somewhat wider hold range.

11. On the Vertical Integrating Network C131, leads 2 and 3 are closely spaced, and lead 2 is the mid-dle lead. On the Sync Take -Off Network C129, leads 1 and 2 are closely spaced, and lead 2 is themiddle one. When replacing either of these units, the leads must be connected as shown in theschematic in order to obtain satisfactory operation.

12. CODE CHANGE - The schematic and parts list as given are for chassis 426, Code C. This chassisincorporated a change (not found in the Code B chassis) to improve the operation of the horizontaloutput circuit. In the Code B chassis the Horizontal Deflection Transformer was of an earlier de-sign. C152 was either one 22 mmf., 10%, 3KV, Disc Capacitor (part No. 157811-1), or two 22 mmf.capacitors wired in parallel.When it is necessary to install a new transformer (part No. 157820-6) in a Code B chassis, it will benecessary to increase the total capacity of C152 to 68 mmf., + 10%, at 3 KV. working voltage. Thismay be done by adding either one or two 22 mmf., capacitors in parallel to the existing capacitors,or by replacing them with a 68 mmf., 10%, 3KV. capacitor (part No. 158215-3).

13. Vertical jitter may be caused by an intermittent contact between ground spring and picture tube,particularly on early production sets that used the brass spring. The trouble may be corrected byreplacing the spring with the new type wire spring, part number 158197. An alternate method is touse a small (1")square of copper screening between the brass spring and the picture tube, taping thescreen to the tube with a plastic tape such as "Scotch" tape.

PRODUCTION CHANGESThe to/lowing changes have been incorporated in later production Chassis 426:

I. R156, R157, and R158, filament shunt resistors (43 ohm, 10%, 2 watt), are replaced by 11174, 126 ohm, 10%, 10 watt resistor, Part No. 158230. The change In theschematic is given in Figure 1. Chassis 426 incorporating this change are stamped with code letter F or later.

a, ha.SKS

VI

rawTEPLOEE

12..0i 26E06Val V009

ar53

4325 0/114 -COLD

,11111T C.V./EN rRESISTOR

1146E LIFE 14TENDERI

6266 6.4MV,02 41.3

RIM

126

2. On Chassis 428 (Code Letter D or later) R132 is a 500 ohm control, Part No. 157955-2. Chassis with earlier code letters have a 1000 ohm control, Part No.157955-1. The change simplifies the sound alignment. When adjusting the Buts Control for a null, the low value resistance makes It easier to find the null.

3. On Chassis 426 (Code Letter D or later) a wiring change was made in the vertical circuit to avoid excessive height by reducing theplate voltage on V110A (verti-cal oscillator tube). However, no parts were added or deleted. The change on the schematic is shown in Figure 2.If it is desired to make this change on earlier chassis, remove the red lead wire between the positive terminal of the electrolytic capacitor C138 and lug 2 of theHeight Control 11146. Then connect a length of hookup wire from positive terminal of C138 to the junction of R150 and 11151 (On the terminal board directly abovethe Height Control).NOTE: On some chassis which did not incorporate the above change, a 1 megohm, 10%, 1/2 watt resistor (Part No. 39374-61) has been inserted between lug 3 ofthe Height Control R1413 and the grid (pin 7) of the V11013. Since this is not used on all chassis, no code letter was assigned. The 1 megohm resistor compen-&Iles for the low overall resistance value of the control when that resistance approaches 4 megohms (lower limit at 20% tolerance). When installing a replace-ment control which has a similar low overall resistance, either of the above methods may be used to decrease the height of the picture.

42

MOST -OFTEN -NEEDED 19U TELEVISION SERVICING INFORMATION

RA -312, 313 CHASSIS

The RA -312 is designed to receive only theVHF channels and the RA -313 is designed to receive all82 UHF and VHF channels. The circuitry of both chassisis of similar design, and some models include a Tonecontrol, plus provisions for the attachment of a phonographwith a conveniently located Phono-TV switch.

ANTENNAJ101

00"NPU

(Courtesy of Allen B. Du Mont Laboratories)

A 41 mc video i-f strip is employed. The video i-fcarrier frequency is 45.75 mc and the sound is at 41.25mc. The video i-f system consists of 3 stagger -tuned bifilar-wound transformer stages utilizing high -gain 6CB6s.Broadband coupling is used between the mixer outputand the first video i-f stage.

N101

L _JHIGH PASS FILTER

TUNER89 013 461

Other tunersalso used.

R.F. AMP.VIOIAI/2 6827

5

R115226

3 5v

O

0

R.F. AMPVI018I/2 6BZ ?

0

1400

O

MI MI

0

2100

RN

0,4

40V

0 1350

C117

I

0010268uur

0106470

C120113).4).i

II

P203 TOJ205

C201,00 0011

2201TOP SLUG45.75mC

220180TSLUG42.25

MC

02013 TOTUNER

OUTPUT

_L 0205-IOU

TOPSLUGL201

41 25AKSOUNDTRAP

- C2031000

80TSLUG.L2Cli

4725mCADJ.

SOUNDTRAP

C1063.91JUr 0 0V 101 0122

8000210

01018000011

CIOS

IA*

Lns

004

1/1:RI04

51<

Iw

R1034704

#1028204

V102

0000

I6--1IL 1,

11

011047

1JUC

MIXER 2000V102A1/2 6U8

RIOT156

-

CII2

U

0108

3v

0R J1 6

1004

LOOAPOINT

0RN

-E.

FINETUNING 5-3

01.10

O

RIP33Iw

0114Io

UV,0113

O

0109109

O

25V

0112*OA

90V

O

OSC.

V2°62,!

0121800IJOr

C1238001J11,

TUNEROUTPUT TO

P208

81108.29

C,24

1ST. VIDEO I.F.V2016CB6

I 020211100

220244 SSMC

0249

V235V 150v

2ND. VIDEO I.F.V2026086

020868"2350

0210470^

20%

680j_00,

220342 351.4C

150v

(Continued on thenext three pages.)

3RD. VIDEO I.F.V203

6086

02110047

-3.50

V201 V202 V203 V204

0 0 0L213

0 0 0 0

0 R 259 AMEG

AGC DIODEV2092 6A56

23500317MEG

i/48, 30%AGC DELAY

USE FOR MODELS WIT? pNONO SWITCH5203 AND TONE CONTROL R32I

L2 4 22215

rTO 0209

0

0317ImEG.

1/4w 30%AGC DELA.

-

235vTv

IINONO

5201

1

1

O0 g:

O 'RI

C.)

O 0

0

0Ia.

OCJ "Fu

Ce; 61;

alE

0 X

cl) 0 0cn ca.(1)

a)

43


NOTES1. All waveforms and voltages were taken under operating conditions.

The receiver was tuned to an average strength TV signal, the Con-trast control rotated fully clockwise and the Noise control was rotatedhilly counter -clockwise.

2. The Noise control and Local -Distance switch consists of a potentio-meter, 11319, and a snap switch, S202. When R319 is rotated fullycounter -clockwise S202 opens (Local position as shown in the sche-matic).

3. Voltages ± 20% of those shown are normal.4. All resistors are 10%, one-half watt, unless otherwise indicated. W. W.

indicates wire wound resistor.5. All capacitors are 20%, 500V, unless otherwise indicated. All capaci-

tors are ceramic, unless indicated as follows: M -mica, P -paper, ±-electrolytic, MP -Molded Paper.

6. Tuner 89 013 461 is used in RA -312 chassis with Phono switch andTone control. Tuner 89 013 561 is used in RA -312 chassis withoutPhono switch and Tone control. Tuner 89 012 912 and filter N202are used with UHF tuner 89 013 293 in RA -313 chassis.

7. In some of the earlier chassis the circuit is as follows:Pin 6 of the 6CB6 2nd video i-f is connected to the junction of 11210and Z203. C218, 11206 are not used. 11222 is a 4.7% 10% 2W resistorconnecting to the + 235 volt line. 11262 is a 120% 10% I/2W resistor,11258 is a 220% 10% 1/2W resistor and 11266 is a 1.8 Meg. 10% 1/2Wresistor. A 180% 10% 1/2W resistor is connected between the junctionof 11261, 11262 and the junction of 11260 and 11266. 11300 is connectedto pin 3 of the 12BH7 Vertical Deflection Amplifier.

K SH

,5v7-

2 TURNS

3

4.4

220444wo

VIDEO DET.V204A

2 64.5

02.35

8215470,3

205.

501

0

00

Du Mont LaboratoriesChassis RA -312, RA -313

511v

COMPOSITEVIDEO PICA VIDEO

TO R268 A 15T TEST POINTSTNC CLIPPER

4 5v L202 0203

If C2 5

1.7V6I

8207IF AGC

TEST POINT

R205Fir AGO

TEST POIN O

A235v

R2584704

START

PULLETSHAFT

TUNER SHAFTDRUM

75v

8256.00.

-CMC05,C .0E0.203

AT 210 LE,

50v

0

R2E9330K

4 5." aRN

82183 SK

1204VIOLET10-^

0261/MEG

P R2605 u(G

75..6257 5202

60 LOCAL -CG D,STANc

6-

219

8262iOOK574

VIDEO AMP.V2056865

C2292 2 00,

111--, 000 --9-1205

0217VIOLET0,5 47004

6.1002,6

T2001

M1HFIC2508266 IX.MEG

210v

R2218 24

C2860

R22241, °'5 6K2Vi

250v

8220

10253330PP,

5202 IS PART OF R319

C256ID

UUF

1ST SYNCCLIPPER

V21068E6

83193mEG 30".NOISE 005780.

DAL 511666 L.SF 5 !cc

PA. 313

8272SON R62,-7,0

25v

0254 82672262.

150100

827.34706

C2I 5

0222000

IS

0

88

2ND SYNCCLIPPERV2I2A11 12AU7

05

C23047

VP

TD52

L2.J456.015,3

L207o 54.02'5L 206wHITE

822454

wW

235v

AR263

18.K.

C2520033002

8264,20K

0221471.1,05.

C222TDFIS

SOUND I.F.V2066Au6

1451

O

oo0 020I32

8235 0231220 01

J203

022022

400VPI RR

#313 15v

15* TO

20% ISO

CONTRAST

8225

150v

0

#226100420%

8238K 20%

150v

0

C.R.T.V401

178.4 20'0'4

MP C223

Zt'Iy

TO P202

O BLUEHV.

°0 0EL BL

R31213I MEGI/0 W20%

BRIGHTNESS

ISO,

0

RED

142

405+

C284RN

2002

8305MEG20%

ifg,

60C

#2461004

USE FOR MODELS WITH PHONO SWITCH5203 AND TONE ft:INTRO,. 8321

I T

751 201

I 711

V2I28V2 12407

45v

O R2T840,5

'544

WPM

C259/001

8280

0260003300v

HOR SWEEP PULSEFROM 7204

0

r°IWIN

0 08295

P206 AFCTEST 601NT

C276

I1V1501 DETECTOR 206,

0oR271

660,5

R273470,5

0258001

1008

ART SFNC PULSETO INT GRATOR

5201 AT vERT 05C,

HOR. PHASE

5.3v

C262`T001

V20482 6AL5

B. V

0261

2002033

44

2206

3

55


TV

PmONO

L

RAT 0 DET. 2

V20764L5

TO C235,#242

NEAR 0207

2204

5203

C2,(1/01

6242228

C239.0047

4 IE-5.700209

10033

TO 0209

0

151. AUDIO 2ND. AUDIOAMP AMP0235 usL C.7,11 ,C2 MODELS M,rnV20% 0222 V208 Im0,./ sm,rem 8 TONE CONTROL

2264T6 01 6V6-GT/202

83124MEG30%

VOLUME

R3218307 R3111% 0 IF.FEG

128 1FAE6 ow 305...- imiw 30% C281 TONE

P0280 VOLUME .00221'208:103v:11

77.-J

USE FOR MODELS *128 P4050 SWITCH 0203 5 TONE CONTROL R321

RETRACE BLANKING0- PULSE FROM VERTOUTPUT TRAP 2201

r -TO 0401

5203 0TV

PROPS

L

R3mB1MEG

24w 20%BRIGHTNESS

TO 0235,8242

NEAR 0207

.500

0

R226'00420%

P C223047

.1400V

HOR. OSC. L208V213 8017 STAR

12 AU 7

82826885%

2000

FN.

C2640047

5% .00V

0263 026522

°.7°UUF .

8.2v

R28308 8285

204

2v%

02740047400V*%

8284680K

83144R322AI 5 MEG

30% iNIKKVERT MOLD

C23601

C2390047

R2A7FAEG

20%

829482X

VERT. 05C° V216A

22 12887

02790022400V*%

1130439

#299564

r0 70v

0°

500

iviloa

USE 11322A FOR MODELS wiTmPmONO SWITCH 8 TONE CONTROL

J

'x'

I rT700 270

829018

MEG

83183 MEG.

30%IMP/

VERT 512E

4000BY BOOST

K4 I35v

8 2,

R320R3228

504 30%4w

HOR HOLD

0286C -289

VJ_1.1. 3500020% ,r,267

0047400v

C266390up

'..:[.-

*%

P 287 1C3907

'51,K IOU':

77 77

235v

A

R28968"20%

8288470820%

WITH v2* FREM0,C0OSC MARLED

NOR. DEFL.AMP.V2I4

6806-GT4100

osE R3228 808 MODELS W,TH ONONOSw,Cm AND TONE CONTROL

160

0269470

F)40'0vi

8203,8 A

C277OAT600V0%

2

C27811297

6000

P300I5K 5%

( C3005

R38.28

( C2005

R28 28

CI

oczRI

228N201

VERT SyNCPULSE FROM

2ND SYNC CLIPPER USE OF SYMBOLS

J-

12002

8252 C287C680,, 1020% 3500214

235V

A

C275.0221600V

8402

TEL r

ER ASST

III

L217DEFLECTION YOKE

3000 BLUE 1201

O

230°0

77RETRACE BLANKING

PULSE TOC282 AT CRT

VERT. DEFLAMP.

Y216 B1/212887

R298 . 02870820^ 0

R31558 20%

ART LIN

750-'

GREEN

4000By BOOST

c>8301 22 a

560,,

5#63930. 22

P 0283

4-2000

400vB BOOST

L 3-- - - -1 A ASolid symbol indicates source of voltage.

Open symbol indicates point to which voltageis applied.Solid bar indicates an adjustable control.

500-,

R316

NOR SIZE

R29168 4w

235V

A

0001.2126,^

DAMPERV2I5

64184-GT

1(88

CO247600210A

L216

000

8292

2

102874

.0. ROOSTPOOV ")

L

L217DEFLECICN

TOME

JTIANGE

J

0L VE#TICAL _ _J

co_

ec

tl

0271 g68

3;(2

%LT

RECTIFIERV216

I83-GT

P20271v

MDR. SW EP PULSE- TO R295 AT NOR.

PHASE OCT

(Continued on the next page.)

45


P201

POWER RECT.0217

720225,0v SUKG

Th AC2878 0286A

4CC'v 3tw

235v MOM5200

111150

6.3VAC

GRN

C2868

1 ,g g

POWERRECT.V2I951140

__ED . NCO,RA -303 GINC.) IN NODE.5F4312 *ITN P1050

Sw0TE11 B TONE CC NT RC,

This is a part of the main circuit shown on previous pages.

(Continued)

RA -312, 313

UNDERCHASSIS VOLTAGE POINTS

8314 VERT MOLDR327I TONE I P11060

000 L5 ONLY1

8319 NOISECONTROL

235V

R306

150V

S203 TV-PHONOSNITCH

NOR NOLO R220OR R322(1(PHONO

MODELS ONLY)

200v

-o -90V3v25v

05C.MIXER

v002GUI

1.

1350

6v 21070z

00-3.5 -

R -F AMP.v 006

BITT202

VERT. HOLDR3220 (P7060MODELS ONLY)

r, _Finn2500 2350 TB13

CI A

VOLUME 11312AOR R3110 PROMO

MODELS ONLY)

C286

L207

( -tr )J205U

Z201

'BIG

235V

P207 0AGE

TEST ACANT

0150v

0

-3201

210

1542

tso

BRIGHTNESS 1312BOR R 11131PHONO

MODELS ONLY)

250

RATIO DET.0207GALS

VIDEO °ET.HOR. PHASE

DET.vilMO V204 -.'"At/. 6ALS

P204-4 3v

2v

1ST. V.I.F.020)

Co GOBSov

Z202

2ND. V. 1. F.02026"6

2100 1500

2v

L201 POWERRECTIFIER

219

250v 5040

Ac

-50vlab

Z203rov

3RD. V.I.F. 2ND. SYNCV203 CLIPPER

1500

"" _00 _"

Tbi0

Z204 !Tv

15V 045v

HOR. PHASEDET.

12t"2AuT3v Ow P2061ST. SYNC CLIPPER AFC TEST

2POINT

'o -

2100 1_, u7 1--I 1-1-35v 25V

GOV

VIDEO AMP. NOISEINVERTER1300v205 210 620

"A5 GO"Te9

1_,1 1-.1

L211L 2ND. AUDIO

AMP0201

SOUND I.F. 9 "6 61v206"U6

145V

P205®TgTZNT 90V

Ts

1ST. AUDIOAMP520)EATS

2009

n nnJ202

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200V 6.20

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1000

102

330v

VERT. OSC.VERT. AMP230 =1

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nnnT B5

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1-1 1-

ez A25002500

2500

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400

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400V R3152500 AC VERT.

POWERLIN

RECTIFIER0217

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250v

C287

400

560V

HOR. DEFL.AMP. zlsvV214

4130 GT A

H.V. RECT.02111

i83-GT

12 KvTHIGH VOLTAGE)

)=,L208NOR

IJ STAB

F0520

235V

4 OV

DAMPER0215

GAXAGT

46


MODELS - 748B, 787A

Emerson reteedoktoge CHASIS - 120179-B

MODELS - 748C, 787B, 796CCHASSIS - 120203-B

MODELS - 777B, 797BCHASSIS - 120204-B

v24 V -24 MODELS - 797C, 798BTELEVISION TUBE TELEVISION TUBE

271VP4 27 RP4CHASSIS

I 20204 -B, 120205-BCHASSIS

120179-8, 120 20 3B

CHASSIS - 120205B......,,,,--..------N.

THESE THREE TUBESARE INTERCHANGEABLE,

V -aI INDICATES GAPS BETWEEN PINS 19 8 (OR 9) ON SOUND

MINIATURE SOCKETS. THIS SHOULD ASSIST DISC.YOU IN INSERTING THESE TUBES WHERE ASOCKET IS OBSTRUCTED FROM VIEW. I

-I BUT DUE TO POSSIBLE-. \ ,23 I VARIATIONS IN INTER-

646105C 8 1 ELECTRODE CAPACITIES,MIXER SEVERAL TUBES MAY

I HAVE TO BE TRIED1 FOR BEST RESULTS

V-22

60R7 V-1A '

. 6807A1ST

OR IMO I F61327 ,II.

V_25

U4g --

i,

.1,23

OSC aMIXER

R 22Hp 6EIK7

SEENOTE BELOW

SOUND <t5LIMITER, Y-9

V-6 16AUe11ST

SOUNDy

I.F,

- 1ST AU010v- i V-2 v-3 V-4 16AU611ST 2ND 3RD VIDEO \ /

V14.0 I.F VI3E9,1 F VIDEO F. DE,TE.E.TOR - V-10

'6V6GT

(Service materialcontinued on thenext nine pages.)

67661V-5

I I 6CS61 ISCB6I I6CE161 16ALS I GCBS\_/ \-/ AUDIOVHF-umF vIDEO AMP OUTPuT

POSITION OFSWITCH v -ii

5U4G RECTIFIERS YSYNC AMPLIFIERSSYNC.SEPARATOR I i

IN CHASSIS120179-13120205-9

V-21 V-20SU4G SWIG

/-L V V 2'

RECT SU4GPOSITION OF

5114G RECTIFIERSiN CHASSiS120203-B L V v-20

/.

DEFLECTION/ YOKE I

'o -a)2AU7

V-17STNCCLAMP 12AU7

a NOISE

L V L VRECT RECT.

120204-B RECT. 5U4G 7

FOCUSING

vI2 INVERTER

HOME PHASEHORi 2

DAMPERHORI2 : UNIT 12"7 DU a HORI2 , .

SYNC PHASE - -

POWERv IS

SAU POWER

DAMPER

V ie66U4

V ISEINVERTER SN

GT

TRANSFORMER TRANSFORMER I niON TRAP VERT OSCv -I341414

wvRECT.

HORIZ.es., OSC. ,re,;T. 6

HORI2.OUTPUT

GT OUTPUT GT

..ANTENNA .4/117COUTSIDE

" P-3i

HORI* PHASECONTROLX 3 FUSE

8 GRIDCONNECTION

To OUTSIDEIF ANTENNAIF u//0.

NOTE THE R F AMP TUBE PRESENTLY USED IS A 88K 7. IN

61307A OR A 6627 MAY BE USED. THESE THREE TUBESBUT DUE TO POSSIBLE VARIATIONS IN INTERELECTRODETUBES MAY HAVE TO BE TRIED FOR BEST RESULTS.

TUBE TROUBLE ANALYSIS

- I VMF ANTENNAOR UHF -VHFANTEMA IFUSED /

THE FUTURE A 6907, * THE PHASEARE INTERCHANGEABLE, LUG TERMINALCAPACITIES, SEVERAL HAS TWO

IT. THE OTHERTHE ONE

CHART FOR CHASSIS

-4_1LOCTION OF TERm11.1.,STRIP SHOWN AT REAR

COIL SIDE OF THE IS FOR CHASSIS 120203-9STRIP ALWAYS AND 120204-B.

WIRES CONNECTED TO STRIP SHOWN BETWEENSIDE HAS ONLY v-12 a V -I3 IS LOCATION

CONTROL GRID WIRE. FOR CHASSIS 120179-8AND 120205-B.

120179-B 120203-B, 120204 -B,120205 -B

SYMPTOM CHECK

Weak or no sound nor video (picture), raster normal -UHF only V-25, D-1, D-2 *Weak or no sound nor video (picture), raster normal -UHF and or VHF V-22, V-23, V-1, V-2, V-3, V-4 Weak or no sound - Video and raster normal UHF and or VHF V-6, V-7, V-8, V-9, V-10Weak or no video - Sound and raster normal UHF and or VHF V-5, V-24Poor or no horizontal nor vertical sync - sound andvideo normal (contrast control makes video darkeror liohter) UHF and or VHF

V-11, V-17

Poor or no horizontal nor vertical sync - Video weakor distorted, raster normal - sound may or may not benormal UHF and or VHF

V-22, V-23, V-1, V-2, V-3, V-4

Poor or no horizontal sync - raster normal and soundnormal (picture locks in vertically) UHF and or VHF V-11, V-12, V-13, V-17Poor or no vertical sync - raster normal and soundnormal (picture locks in horizontally) UHF and or VHF V-11, V-17, V-18Horizontal line (no vertical sweep) - sound normal - UHF and or VHF V-18, V-19Insufficient horizontal size, sound & video normal - UHF and or VHF V-14, V-16, V-20. V-21 V-26**Insufficient vertical size, or white horizontalbar in picture, horizontal size OK UHF and or VHF V-19No sound, no raster - tubes lit UHF and or VHF Fuse, V-20, V-21No sound, no raster - tubes not lit - UHF and or VHF Plug connection in wall socket,

ON -OFF switch, line cord.

By roster we mean the illuminated scanning lines.

* Another very common fault is a shorted or open circuit antenna connection to set.** Some 120179-B chassis used two 6AX4GT tubes (V-16, V-26) instead of one 6AU4G (V-16).

47

PR

OD

UC

TIO

N C

HA

NG

ES

I.T

he w

atta

ge o

f res

isto

rs R

-108

(47

0 oh

ms)

and

R-1

10 (

33,0

00 o

hm)

have

incr

ease

d fr

om 1

/2 w

att t

o 1

wat

t to

prev

ent t

hese

res

isto

rs fr

om o

verlo

adin

g at

ext

rem

e se

tting

s of

the

vert

ical

siz

e an

d lin

earit

y co

ntro

ls. C

hass

isin

corp

orat

ing

this

cha

nge

are

code

d as

follo

ws.

I.=

1201

79-B

A 1

2020

3-B

, 120

204-

B, 1

2020

5-B

- In

itial

Pro

duct

ion

:1,.

1-. ,g

2.F

or s

tand

ardi

zatio

n pu

rpos

es th

e tw

o 6A

X4G

T d

ampe

r tu

bes

(V-1

6, V

-26)

hav

e be

en r

epla

ced

with

a s

ingl

e 6A

U4G

T...

-da

mpe

r tu

be V

-16)

. Cha

ssis

inco

rpor

atin

g th

is c

hang

e ar

e co

ded

as fo

llow

s.

zit\

1202

03-B

, 120

204-

B, 1

2020

5-B

- In

itial

Pro

duct

ion

I.,.

1201

79-B

o-3.

Due

to c

ompo

nent

var

iatio

ns it

was

foun

d ne

cess

ary

to c

hang

e R

-74

from

330

K to

390

K 1

/2 w

att i

n or

der

to e

limi-

1 §:

1Tna

te a

n ov

erdr

ive

bar

that

has

dev

elop

ed (

whi

te v

ertic

al li

ne in

ras

ter)

.A

t the

sam

e tim

e a

100m

mf 4

kv. c

onde

nser

(pt

. No.

928

114)

was

add

ed b

etw

een

term

inal

s 4

and

8of

the

horiz

onta

l

outp

ut tr

ansf

orm

er to

incr

ease

wid

th fo

r lo

w li

ne v

olta

ge o

pera

tion.

Cha

ssis

inco

rpor

atin

g th

ese

chan

ges

are

code

d

as fo

llow

s.12

0179

-B12

0203

-B, 1

2020

4-B

- In

itial

Pro

duct

ion

1202

05-B

A

NO

TE

: Tria

ngle

on th

e 12

0205

-B c

hass

is s

igni

fies

the

use

of a

27R

P4

pict

ure

tube

inst

ead

of a

27E

P4.

Sin

ce

the

27R

P4

has

an a

cqua

dag

coat

ing

it fo

rms

it's

own

Hi -

volta

ge fi

lter

cond

ense

ran

d as

a r

esul

t C-6

1 (5

00 m

mf,

30kv

.) a

nd R

-84

(100

K,

1w

att)

are

om

itted

. The

27R

P4

is u

sed

on th

e 12

0203

-d a

nd 1

2020

4-B

chas

sis.

4

SLA

CK

BLA

CK

10 U

000

1 m00

< 0ro

oa

L

1 N

O

o <

m90

$- lt2

r

1 L

ro.7

171-

70. CA

r -

L_

300

0111

1 L

INE

I IN

-J

ED

cp4

(I)

11)

cri

0cn

c.n

Cl

ED

0+cn-

cn'1 cD

0"'

1--,

a)-

)

Z''

2 C

rcl

10 -E

D0

...-3

oo

ra.

-'a)

(f)

cl, co

O

,--4

.

.-a.

. va

r,.

O1-

-,E

n1 ED

Ev

O 0 ,'

n..,

CI

(1)

0E

D0

c..3

11&

)td

co0-

ED

n+-.

(.1)

IMOST -OFTEN -NEEDED 195 TELEVISION SERVICING INFORMATIONwmc

DSOUND VOLTAGE SOUND VOLTAGE

LIMITER vAArs ATH DISCRIMINATOR vARIES WITH

V- 7 SIGNAL V-8 SIGNALA .1

6AU6 6AL5, 1 7 ..,_ ov

-.9v57v 1570 or -I

R-34

C9470

0

-1600141

:ME 00T 7 6

C -301C-324 68 - 5000

MAE'MMf

VIDEOp -P

3R0MAP

V-36CB6 ISO

Lv.

R -I58200 'C

C -1268

30F

113,,14

O

68 Ux 0 0

L - 6

GC

00

5000106K

22

1875 C

C-14

MMF8 ° 170

C-1310003414F

R-/6mEG

VIDEO TO Sr,

re77_f_875 c P S

C-47.001

7875 L P

R-66

46 228 14 - 0022 .05.MOO AT."

12AU7 ' R-6582K

. SYNC. PHASERTER IS HOR1Z.3E DETECTOR I3

12A V -I28

0-43

70IMF

C - 5I

i3v

L-73. 0 I

C-72.0047

8-97100K

R-64B2K

R-396800

-J.661rN Do T 7 6

R-42 R-44iOOK 68K

R -41tOOK

R-17IOTA

68

1,7B 75CP5

C-SI100 MMF

8-H-C-49.001

C -SO

I.015R-69- 120010011

7875 C PS

ON1 05

VALprAgs.2v 3

I(\ C-48

.001

HEIGHT OF wAvESHAPEg8RfEa;NI.TIL

CONTROL.

.444;494 v Pao

+275 V.

R-98ISO K

30 CPS

7875 CPS

30 CPS

VERTICALOSCILL ATOR

V -18A V -18B6SN7GT 70

V I

C -74.0047

R-101820K

751VERTHOLDCONTROL

30 CPS

7875 C P S

+2750

90VTO 1250

P -P

R.4510 MEG

C2,3 C-340022

Imm' 1"--

-43

D

MA'IO MEG

L 7

A. 68 UH

C .1811000MMF I

1 r C C

C 53 0047

10R-70 L-13IS K032v V -13A V -I3

6SN7GTHORtZ. OSCILLATOR

AUDIO AMPLIFIER(*ACC CLAMP

V-96AV6

92

IR-472208

R-46I MEG v

VOLUMECONTROL

7 v TO 9.401

Z HOR1Z ZHORIZBALANCE HOLDCONTROL CONTROL

AUDIOOUTPulV -I0

6V6GT

23Sv 85 of

001 R-49 R-50470 1500

+160V +2900

C-205000 SUP

'Or

/ ''FilFTT-5

(-11I°-10,00,1

20014

8.5v

L Et

40uH

R-224700

2150

0

R-114

VIDEOAMPLIFIER

V -S

6C86

11C

8-2 P-2iND

- 3980

pOy

30 C P 5 070 C P

0 0477 250u

C -23O1000 MME

0-241500

CONTRASTCONTROL

8-23MEG

C ,(2)2

C-57 R -79.001 66

C-56390MMF

/7875 CPS

74330K

`SEE .3

OS

-105EG

C-7711

+ C-78

-1

875 CPS

R 272 OK -

BRIGHTNESSCONTROL

+1600. +2 5v

HORIZONTALOUTPUT

V-146CD6G

C-59 I

R-110100

T- 9

700R-IIS

47

C-83100MMF

SEEPAGE

243

+ 2TSV

R-304705

HIGH VOLTAGERECTIFIER

V -I5IB3GT

2.7

R -84100K,

7. 500 '1.--MMF

V-166AU4 GT

ELL DOOW H AMMIT PPER

L-14HORIZSIZE

14 7L-15

C-60 1004.CONTROL

.15000

ed3.0.3/3"-WV-46%-eR -ill R-118 R-11961300 6800 6600 vs

R-110

VERT. OUTPUTV-19

6W6 GT

-.5v TO 2.4V 5

C-79100 400

n-106 T R-1082 2

470MEG -

R-107511

VERT

30 C PS LIN. CONTROL

.e±r

33K

,SEE

7-10

+ 2750

EMERSON

SCHEMATICDIAGRAMCHASSIS A120 I 79-B /B\I20203 -BI20204 -B AI20205 -B /A\

RAGNIN

C-2666X- I

BOTTOM VIEWOF SOCKET

PICTURETUBEV-24

2 7RP4OR

2 7EP 4(SEE PAGE 24 NOTE)

+ BOOST 580V

C-80DI

275

SEEPAGE 24

WI

6REE

+ 275 V.

S CPS

500v

X-4BOTTOM VIEW

OF SOCKET

O 12

I-1 _--4.7 7ION TRAP

m-i-T'VC 1=0*---__ 5-2FOCUSER AND ANTI PINCENTERING 18,000

CUSHIONUNIT VOLTS MAGNET0

Gm VOLTAGE LEAD

1, --SEE NOTE

X-6

10K

x-5SEE .2

C-1:12

P-4

P-6

P-5

DEFLECTION YOKEASSEMBLYr

I L-IB404.12

II COILS

C-81100 NNE

3 I

L-17 1

VERTCOILS

-J

THIS HASH DUE TO SUPERIMPOSED SCOPE IMAGES ISNORMAL AND NAY VARY IN AMPLITUDE DEPENDING ONTYPE OF PICTURE INFORMATION AND SETTING OFHORIZONTAL MOLD CONTROL.

49

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONEMERSON Television Chassis 120179-B, 120203-B, 120204-B, 120205-B, continued

Models 7483, 784C, 787A, 787B and 786C incorporating chassis 120179-B and 120203-B are ALL CHANNELUHF - VHF RECEIVERS.' Combination VHF and UHF tuning is achieved through the use of two tuners which areconnected to the same tuning knobs making VHF or UHF channel tuning very simple. The VHF cascode turrettuner has 13 positions (one more than the conventional type), 12 being used for VHF reception, (channels 2 to 13),while the 13th or UHF position is used to activate the proper UHF circuits and provides additional amplification forthe converted 40 me UHF signals.

Models 777B, 797B, 797C and 7988 incorporating chassis 120204-8 and 120205-B are VHF receivers which can,if desired, be easily adapted to UHF by means of interchangeable channel strips or by use of an external converter.

0000TVIRONIT n fJI BATTING LU'S

to olOviDuAL cm.. *TOMO - - - - - mu orc-7,-7-4617-. ITM9=Oo TkOMIT1011. POETS ASH okOADOMO to Toff /AMON PI TYCO INSIOCTIVO Ar.MI

Toe 3V011.O MAP CIO 0/ 1/2 V-22 0.44LOCATO IOo

3- ALL INSMIAOC2 VAL. A*2 /o OoS oODO,ANO ,CAPAVTAsCr Yalta* OMo oo, 6...22 OTOO / 60002.*2 3,0,2D / C 10.

t."4 I/0BAL.300ANT. INPUT L 4

0

ARC 0

OOP

1/2 V-226BK7

-a° 140 TC-2UHF STRIP 70s113 TM POSITION,

960110

66007 `Li so,j,. C-5 I.,.

1000.0[

* 270 V 0--1,63

* 160V 0 ".""'630.0 "''

VIDEOI. FOUTPUT

IiaSR -,m

1Amcce l<

NOSS*C-17

FINETUNING

1/2 V-236J6 '"

*TOO OA

T -I

4.4 TO C -4I.04 34

L

MCI, mj4-7

!

TEST POINT

12-11

y. 1/2 V-23IZ 6J6

c-oo

TC -e

21

c-61-3

STRIP/3 TN KOITIOO1j 960 7 70

Woo.

TUNER PART NO. 470712 748 rumt MOT, SCHEMATIC PART NO, 950246NOTE

MIT 0. TO POONELE rMIAYT K

TIOKI 1011.11HLEEMOTIC EXCAM.1".."".Tune' MT nAvl TO OE TREIO FOP IMMILTS.TE

SCHEMATIC DIAGRAM OF VHF TUNER 470712 USED ON UHF -VHF CHASSIS 120179-B, 120203-8

ANT. INPUTSAL.300.11

ABC 0

+270V.0

+160V.0

6.3V.

/S

ROA980630

R.FANF1/2 V-226807

L 3 41 I

Ls

C -II TO C -IS PI NOS. I40407

TUNER PART NO. 470696

R 1

-7

L-9

.

AK MOUNTED oM MOIVIOUALCOMMEL TIMOIT.181704 KNOTS 400 ht...0IN

9111174MCE WLUES Aft9

rica CORER Of TRE111 91171 0110ELOCATMM 11.01.1 E.01 TME TUOIE11.

3- 4U.111 OM. AMO CANCITAITCEMK IN NMI MUM* OTHEIMMEMOICATEO.

I .1.M SONE TIME"

' : L-10 Ti L-12 nite /.1:.*.c`T'.°.7.c:f.:.

--i..,

.. 1 4.111 UN 1000 ,,,, g,.

MID L-13 1410633

1L-11 1/s V-23 194 -, _VIDEOT- I

960634

9.I

-... I C 1 I OUTPUT1 C J6

7

-as -a4C-6

4.

R -I0WC

IV.' 1960831

4.-

L. -J

'OSCILLATOR11/2 V-23I 646

MECHANICAL PARTS CAN BE ORDERED BY NAMINGPARTS FUNCTION AND NOTING THE TUNER PT NO.

NOTE: THE 8.F AMP TUBE PRESENTLY USED IS A 6807. IN TIE FUTURE A 8007, SOOTS OR A 8027 NAYDE MO. TREK 7141411 TOMS ENE NOTZECNANSEASLE. ROT DOE TO POSSIIIL VAR! AT IONS IN

IN RODE CAPACITIES. TUBES WY NAVE TO SE TR1(0 FOR REST NRSULTII

E$01

TEST POINT

A2 -A13

9110C- 13Si-03

M0 I

V: I

SCHEMATIC PART NO. 950219

SCHEMATIC DIAGRAM OF TURRET TYPE TUNER USED ON VHF CHASSIS 120204-B, 120205-B

50


EMERSON Television Chassis 120179B, 120203B, 120204B, 120205B, (Continued)

ALIGNMENT V.H.F.ALIGP'MENT

STANDARD

SIGNAL GEN.

ISUPPLIES COUPLE IN A MANNER TNAT MILL

a. Equipment Required - A sweep generator, (10 MC.MARKER SIGNAL) PROVIOE JUST ENOUGH MARKER

TO ME DISCERNABLE WITHOUTsweep with center frequency of 44 MC. plus allnecessary R. F . sweep frequencies as listed in R.F. i'Table), accurate marker generator, oscilloscope

GROUNO TO CHASSIS

AFFECTING THE 0111SERVE0 RESPONSE

Ito" ..-...,I '0,'and V.T.V.M. are required for alignment. The

marker generator must supply frequencies of 4.5.....

MC., 40 to 48 MC. and 50 to 216 MC.

b. Alignment Points - The location of all I .F. trans-formers, Tuned Circuits, and trimmers shown in

SWEEP GENERATOR

WITH SO OHM

OUTPUT

50 JL

V. 14F.

TERMINALS

Figure 9 . ISO"rot

TV R. F. & MIXER ALIGNMENT (V. H. F. ) NOTE. SWEEP GENERATOR uWITH 300 OHM

Connect 3 volt bias battery to both I .F. and R.F. OUTPUT CONNECTDIRECTLY TO ANT.AGC. circuits, positive terminal to chassis, nega-

flue terminal to junction of R-19, C-19, C-18. TERMINALS.

Add a jumper wire from this junction to junctionof R-10, R-16, C-8 so that the bias battery is also Figure 5 . GENERATOR CONNECTIONS FOR TELEVISIONapplied to I .F. AGC. R.F. CHANNEL ALIGNMENT.

SWEEP & MARKERGENERATOR MARKER GEN.

OSCILLOSCOPE MISCELLANEOUS TRIMMER TYPE OF ADJUSTMENT

CONNECTIONS FREQ.RANGE FREQ.

CONNECTIONS INSTRUCT IONS OR SLUG AND OUTPUT INDICATION

Connect asshown in Fig. 5and adjustsweep controls

Channel112

209.75 MC.Sound Carrier

205.25 MC.

Vert. input ofscope through10K resistor totest point on

Set Channel Selector to 112

NOTE

Keep output of R.F. Marker

C-2R.F. Amp.

InputTrimmer

Adjust Trimmers C-2, C-5 and C-6to obtain response shown in Fig. 6

IMPORTANT: When adjustingtrimmers C-2, C-5 and C-6 it willfor width so

that completechannel re-sponse may be

207 MC.CenterFreq.

Pix Carrier tuner Fig. 9Low side tochassis

Generator at a level thatprovides a readable markerbut does not distort thecurve that is being observed

C-5R.F. PlateTrimmer

be noted that the bond pass char -acteristic can be broadened bysacrificing amplitude. It is unde-sirable to overly broaden theobserved as

shown in Fig. 6 on the scope.C-6

MixerGrid

Trimmer

curve as that would result in aloss of sensitivity.

113213 MC.

'215.75 MC.211.25 MC.

Set Channel Selector to 113(See Note Above)

The r -f band pass characteristic of the othertelevision channels should now be checkedwithout disturbing the settings of trimmersC-2, C-5 C-6. Adjust the

#11201 MC.

'203.75 MC.*199.25 MC.


and r -f sweep gen-erator and marker generator for operation onthe other television channels, observing posi-

#10195 MC.

*197.75 MC.193.25 MC.


tion of both the sound carrier and picture car -tier markers.

19189 MC.

191.75 MC.187.25 MC.

Set Channel Selector to 19(See Note Above) "K OW

...........

#8 185.75 MC. Set Channel Selector to 18 Ial('

zrt.,-,7-183 MC. 181725 MC. (See Note Above) r°

1 r 171`.'7:: X.,* ..

Same /7 179.75 MC.175.25

Sameas

Set Channel Selector to 17 ias 177 MC. MC. (See Note Above) ,t, soAboveAbove

1685 MC.

87.75 MC. 83.25 MC.


' OUSTRESPONSESIDEIC, MSPIAIM A.

#5 81.75 MC. Set Channel Selector to 15 li''

IIILe79 MC. 77.25 MC. (See Note Above)

#469 MC.

71.75 MC. 67.25 MC.


Figure 6 -- TUNER RESPONSE OJRVESHOWING BAND-PASS LIMITS.

1363 MC.

65.75 MC." 61.25 MC.


The response for all channels should meet withthe requirements of Fig. 6. To do so it may be

by changing12

57 MC. 59.75 MC.

55.25 MC.Set Channel Selector to 12

(See Note Above)

necessary to compromise slightlythe initial channel 112 adjustments of C-2,C-5 and C-6 while switched to channel whichdoes not conform.

Sound Carrier MarkerPicture Carrier Marker

51


I.F.

EMERSON Television Chassis 120179B, 120203B, 120204B, 120205BAlignment Information, Continued

ALIGNMENT

1) Tune receiver to unused Channel 10 or 12.2) Connect 3 volt bias battery with negative terminal to I.F. AGC. (Junction R-10, C-8, R-16)

positive terminal to chassis.3) Connect D.C. V.T.V.M. to video test point, low side to chassis.4) Connect terminated marker generator to floating shield of converted tube V-23 6J6. (Shield raised

slightly so that it does not make contact with chassis). Use unmodulated marker. See Fig. 8.

MARKERGENERATOR ADJUST PROCEDURE

45.75 MC.Unmodulated

T-4

Peak for maximum response. Adjust output of signal generator so thatmaximum response does not produce more than -2V. D.C. on V.T.V.M.

43.2 MC.Unmodulated T-3

42.0 MC.Unmodulated T-2

45.0 MC.Unmodulated

L-3T-1

41.25 MC.Unmodulated

L-2Adjust trap for minimum response. Increase output from signal generator so that atrue minimum position can be found.

5) Connect vertical input of an oscilloscope instead of V.T.V.M. to video test point with vertical scopegain set at, or near, maximum. (Horizontal scope sweep set at 400 cycles).

MARKERGENERATOR ADJUST PROCEDURE

47.25 MC.400 CyclesAmp. Mod.

L-1 With signal generator set at maximum output, adjust L-1 for minimum vertical re -sponse on scope.

6) Now that all the I.F. coils and transformers have been set, the overall response can be observed andadjusted if necessary.

SIGNAL GENERATOR INPUTMEASURINGADJUSTINSTRUMENT

PROCEDURE

CONNECTIONFREQUENCY

SWEEP MARKER

Connect terminatedsweep and markeras shown in Fig. 8

Centerfrequency44 MC.10 MC.Sweep

45.75 MC. Scopeconnectedto VideoTest Point lowside to chassis

1-4 If 45.75 MC. doesn't lie from 60 to70% down adjust 1-4 (see fig. 7 ) fortolerances. *

Providing overalltilt is not as specified,TRAPS L-1 and L-2ING OVERALL I.F.

KEEP OUTPUT OF SIGNALTUBE OVERLOAD MIGHT

Alllk,

curve

MUSTRESPONSE

is withinrepeat

BE

GENERATORRESULT

60%

I45.75

MC. -01

tolerancesentire alignmentADJUSTED

CURVE.

AS LOW

AND THE RESPONSE

PERMISIBLE20% EITHER

TO 70%

MC.

47.25 .MC.

as shown below, no further adjustments are needed. If band width orprocedure. If still out then a slight retouching is permissible.

AS INDICATED ABOVE. DO NOT RE -ADJUST WHILE OBSERV-

AS POSSIBLE WHEN OBSERVING THE OVERALL I.F. SHAPE SINCEWILL APPEAR INCORRECTLY FLAT AND WIDE.

TILTWAY

NOTE: It may be impossible toobserve the 47.25 MC. markerwith the average service equip-ment due to the high attenuationof trap L-1 (adjacent sound).

ADJACENTSOUND

Figure 7. OVERALL I.F. RESPONSE CURVE

.....20%MAY

3.5 TO

41.25 MC.

52


NAR'KEN s

FLoATNGSHIELD

FLOATING SHIELD

UHF TUNERLOCATED AOvETHE SIAS TUNESON CHASSIS Iearfro

TOSWEEP

GENERATOR

CONNECT INPLACE OF V.Y.Y.M.WHEN NEEDED.

TO SIT HASSiS el THIS POSITIONBLOCK OF WOOD BETWEEN THE NISH IVOLTASE CASEAND TIC WORK BENCH.

Figure 8. CONNECTIONS FOR I.F. ALIGNMENT

All instrument leads should be dressed as shown andkept as short as possible to prevent interaction betweeninput and output leads. Failure to do this may result inan unstable response indication.

NOTE: It is important that the output cable of the sweepand marker generator be properly terminated in their char-acteristic impedance which is usually from 50 to 75 ohms.If this termination has not been built into the end of thecable by the instrument manufacturer * then a resistor ofthe proper value (characteristic impedance) should beconnected across the output of each generator cable asshown above.

*If in doubt check your instruction book which is issuedby the test equipment manufacturer.

A2 -A13ACCESSIBLETHRU HOLEIN TUNERCHASSIS

1 C-3

TUNINGTUNING

TESTPOINT

VHFTUNER

ALIGNMENTPOINTS FOR

CHASSIS12020413120205-6

T- I45.0 MC.

C -I I.F. TRAP ADJUST-MENT TUNED IN FIELD TOREDUCE INTERFERENCE ONCHANNEL 2 DUE TO NEARBYTRANSMITTERS BROADCASTINGIN THE I.F. RANGE. IF NOINTERFERENCE IS PRESENTTURN SCREW ALL THE WAY IN.

TESTPOINT

T -A

A2 -A13, 1

1

ACCESSIBLE I,'

THRU HOLE I C-3IN TUNER 1 1 FINECHASSIS 1 , TUNING

II

SLOTTEDSLUG

BOTTOMADJUSTMENT ADJUSTMENT ADJUSTMENT Of ADJUSTMENT OFUSE FIBRE WITH SECONDARY WITH PRIMARy WITHALIGNMENT OF ALIGNMENT SIDE 'A OF SIOE '11. OF

TOOL TOOL ALIGNMENT TOOL ALIGNMENT TOOL

EMERSON TelevisionChassis 120179B, 120203B,

120204B, 120205B

Alignment Information(Continued)

.opr- SIDE Ir HEa HEAD FINN ALI...EMT TOOL SIDE\oTOP OR BOTTOM ADJUSTMENT

FIGURE 8A

NOTE, C-4 OSC. TRIMMER CAN BE ADJUSTED TOCOMPENSATE FOR VARIATIONS IN INTER -ELECTRODE CAPACITIES OF 6J6 OSC. TUBE.

UHFTUNER

L-5HIGHPASSFILTER

C-5

T -I5.0 MC.

VHFTUNER

ALIGNMENTPOINTS FOR

CHASSIS1201711-9120203-B

FRONT OF CHASSIS

T-2/42.0 MC.BOTTOM w

L-3 45.0 MC, TOP OR BOTTOM*

L -I ADJACENT SOUND TRAP47.26 MC. TOP OR BOTTOM

L-2 SOUND CARRIER TRAP41.25MC. TOP OR BOTTOM

T-343.2 MC.BOTTOM *

T-445.76MC.BOTTOM *

T-64.5 MC.

TOP ANDT-6 BOTTOM'S

4.6 MC.TOP OR BOTTOM"

* SEE NOTE UNDER STEP 4 PAGE 9.

T-7.5 MC.TOP ANDBOTTOM

SECONDARYON TOP *

L 12.5 MC.TRAPTOP OR *BOTTOM

Figure 9. LOCATION OF ALIGNMENT POINTS (TOP VIEW)

53


EMERSON Television Chassis 120179B, 120203B, 120204B, 120205B, (Continued)Additional Alignment Information

R.F. OSCILLATOR ALIGNMENT (V.H.F.)

1. Connect maker and sweep generator as shown in Figure 5, low side to chassis.

2. Connect scope to junction L-8, R-22, low side to chassis or video test point.3. Connect 3 volt bias battery as described under R.F. alignment Page 8.

4. Before undertaking oscillator alignment be sure I.F. circuits are correctly aligned for band pass characteristic and trapsettings.

5. During oscillator alignment, it is necessary to set the fine tuning control so that the tooth on the fine tuning corn pointsdownward. On the 470712 tuner the flat of the fine tuning shaft should point downward with respect to the bottom of thechassis.

MARKERSIGNAL

GENERATORFREQUENCY

SWEEPGENERATORFREQUENCY

MISCELLANEOUSINSTRUCTIONS

TRIMMEROR

SLUG

TYPE OF ADJUSTMENTAND OUTPUT INDICATION

209.75 MC.**205.25 MC.

Channel#12

CenterFrequency

207 MC.10 MC.

Sweep

Be sure that fine tuning control hasbeen properly positioned (tooth on thecam pointing down)

NOTE

During this step and thru-out all suc-seeding steps it is necessary to:

1. Keep output of sweep generator at alevel that does not allow the readingon a VTVM to exceed minus 1 voltwhen connected across video detectorload at minimum sweep width.

2. Keep output of standard signal gen-erator at a level that provides areadable marker but does not distortthe curve that is being observed onthe scope.

AdjustSlugA-12

NOTE: Before making the following adjustment,advance the vertical gain control on the scope inorder to magnify the sound trap portion of the re -sponse curve.

Then, use a non-metallic screwdriver to adjustchannel #12 oscillator slug (accessible thru holeon front of r -f tuner unit)and shift response curveso that sound carrier marker is located at theposition indicated below.

Now reduce gain control setting of scope to re -store pattern to normal amplitude and observeposition of picture carrier marker. This markershould appear on the high frequency side of thecharacteristic curve. The amplitude of the pic-hire carrier should be between 60 and 70% downfrom peak response.

*215.75 MC."211.25 MC.203.75 MC.

199.25 MC.*197.75 MC.

**193.25 MC.I91.75 MC.

187.25 MC.'185.75 MC.

"181.25 MC.179.75 MC.

175.25 MC. 87.75 MC.

83.25 MC. 81.75 MC.

77.25 MC. 71.75 MC.

67.25 MC. 65.75 MC.

61.25 MC.* 59.75 MC.

55.25 MC.

Channel 013213 MC.

Channel #11201 MC.

Channel 110195 MC

Channel #9189 MC.

Channel #8183 MC.

Channel #7177 MC.

Channel #685 MC.

Channel #579 MC.

Channel #469 MC.

Channel #363 MC.

Channel #2.57 MC.

Set Channel Selector to #13(See note above)











Adjust the r -f sweep generator and marker generator for op -eration on other television channels; set marker generator tosound carrier frequency. After setting Channel Selector to cor-responding channel, adjust oscillator slug thru hole on front ofr -f tuner unit. (A-2 to A-13)

This permits response curve to be shifted so that sound carriermarker will appear at the position indicated below.

60 TO70%

+ PIX I.F.45.75 MC.

SOUND I. F.

41.25 MC.

TYPICAL OVERALL RESPONSE CURVE

NOTE: Make sure that cam on fine tuning control shaft re-mains properly positioned during this step (tooth on the cornpointing downward).

NOTE: If an unsatisfactory overall response is obtained for a particular channel, observe R -F amp. and Mixerresponse curve for that channel (as described in R -F Amp. and Mixer Alignment Table). If characteristic curvedoes not conform reasonably well within the typical curve shown in Figure 6 then do the following things:

1. Check method of connecting scope, voltmeter and generator leads to eliminate possible distortion ofobserved response, or:

2. Attempt to obtain a better compromise for R.F. response on all channels by realigning R -F Amp. andMixer circuits, or:

3. Try replacing Antenna, R -F and Oscillator coils for the particular channel.

'Sound Carrier MarkerPicture Carrier Marker

R,F. OSCILLATOR ALIGNMENT PROCEDURE

54


EMERSON Television Chassis 120179B, 120203B, 120204B, 120205B,Alignment Information, Continued

SOUND ALIGNMENT

(A) USING 4.5 mc UNMODULATED SIGNAL GENERATOR (B)

1) Short pin #1 of V-3 Chassis with short jumper wire.

2) Keep output of signal generator low so as to pro-vide a sharp meter indication with adjustment oftransformers.

USING TRANSMITTED TV AIR SIGNAL

1) Connect antenna and tune to a good on the air TVstation.

2) Adjust fine tuning control for best picture.

3) Adjust antenna coupling for moderate signal so as toprovide a sharp meter indication with adjustment oftransformers.

4) Meter reading may pulsate due to changes in signalstrength; do not confuse with a peak adjustment.

STEPSIGNAL GENERATOR INPUT MEASURING

INSTRUMENT ADJUST PROCEDURECONNECTION FREQUENCY

1

Marker Gen. through.01 MF to Pin 7 ofV-4 low side tochassis.

Connect antenna andtune in a good trans-mitted TV. signal(any channel)

4.5 MC(ljnmodulated)

A good on the airTV. channel

Conntec D.C. V.T.V.M.(negative scale)through 10K Resistorto Junction of C-30,R-35, R-36 - low sideto chassis.

T-5Topor

Bottom

T-6Top and

Bottom

Peak for maximum voltage.Adjust output of signalgenerator to produce about aone volt D.C. rise on meter(1 volt above noise* voltage)

If T.V. signal is usedadjust ant. coupling toreceiver to produce about thesome voltage rise.

2 Same asabove.

Same asabove.

Connect V.T.V.M.through 10K

Junction of R-44,C-34 - low sideto chassis.

T-7Top andBottom(Dis-crimi-

nator ontop)

A) Detune Discriminatorsecondary T-7 for maxi -mum negativereading.

B) Adjust primary T-7 formaximum negative meterreading.

C) Readjust Discriminatorsecondary (towards originalsetting) for zero D.C. read-ing on V.T.V.M.

D) Check Audio, if distortedrepeat steps A - C.

* The noise voltage is measured under no signal conditions (antenna terminals shor ed directly at tuner by meansof a short jumper wire; or disconnect 4.5 MC. generator if procedure (A) above is followed.)

4.5 MC VIDEO TRAP ALIGNMENT (L-12)

1. Connect crystal controlled 4.5 mc. signal generator through a .01 mf. condenser to the grid of the video ampli-fier tube (Pin 1 of V-5, 6CB6) low side to chassis.

2. Set contrast control for maximum contrast (fully clockwise).3. Connect a V.T.V.M. (D.C. scale) through an R.F. probe to the cathode of the picture tube (Pin 11, yellow lead)

low side to chassis.4. Adjust the 4.5 mc. trap L-12 for minimum reading on the V.T.V.M.

If a crystal controlled generator is not available the video trap can be adjusted in the field by setting the fine tun-ing control for maximum 4.5 mc. in picture and adjusting the 4.5 mc. trap (L-12) until this 4.5 mc. beat note is re-duced. Be sure that video ringing is not introduced from this adjustment since this indicates the trap was aligned attoo low a frequency.

ALIGNMENT (UHF TUNER)

The alignment of the tuner is factory set and will actually not require any additional adjustments other than tocompensate for differences in 6J6 oscillator tubes. Because of this fact, the only adjustment to be made in the fieldis trimmer C-7 which is located next to the 6J6 oscillator tube. (See Figure 9)

This trimmer is normally set at the factory to track the highest U. H.F.channel (83). This must be done with aU. H.F. sweep and marker generator. In the field however, this equipment is not readily available and C-7 shouldtherefore be used to track the highest U. H.F. channel received in the area. It is usually best to try a few 6J6 tubesuntil one is found which more nearly resembles the original, thus requiring only a slight adjustment of C-7.

55


EMERSON

CONDITIONS

The

Duenoticedto difference

The

I. Antenna

2. Line

3. 3USED

4. All

5. All6. All

7. Resistance

8. N.C.

WAVE SHAPE

The

Slight

Whensible

The

Tocharacteristics1. Connect

2. Low3. The

NOTE:

Television Chassis 120179B,

FOR TAKING VOLTAGE AND RESISTANCE READINGS

voltage and resistance measurements listed were taken on chassis

to component variations, voltage and resistance readings mayif chassis is not coded as mentioned above. Slight variations

in coding for same triangle change.

deflection yoke and high voltage circuits were connected to take

disconnected and antenna terminals shorted on tuner and connected

voltage 117 volts (Disconnect power for resistance readings).

volt bias battery connected to A.G.C. circuit, positive terminal to chassis,FOR VOLTAGE READINGS ONLY.

controls in position for normal picture. (Varied when it directly

measurements taken with a vacuum tube voltmeter and ohmmeter.

readings listed in tables were taken between points shown and chassis.

readings are given in ohms unless otherwise noted.

denotes no connection.

ANALYSIS CHART

waveshapes shown were taken on chassis 120205-B coded triangle.

peak to peak voltage differences may be noticed on chassis

taking waveshapes on chassis 120179-B, 120203-B and 120204-Bdue to differences in chassis coding for the same change. See

peak to peak voltage given may also vary slightly depending

accurately observe the wave shapes, the relatively high input capacityof the television set.

antenna and tune receiver to channel where best reception has

end of the probe is connected to CHASSIS and the contrast control

30 and 7875 C.P.S. oscilloscope sweep settings are used so as

A wave shape seen in your oscilloscope may be upside downstages of amplification in the oscilloscope used.

RESISTANCE

120203B, 120204B,

120205-B, coded with

vary slightly from thosemay be noticed on chassis

the following readings

to chassis (use short

negative terminal to

effects reading).

120205B, (Continued)

a triangle. Agiven here. Slight variations may also

120179-B, 120203-B & 120204-B

and waveshapes.

leads).

junction of R-10, C-8, R-16 BIAS BATTERY

a slight peak to peak variations arePage 24 for further information.

variations.

must be reduced so as not to change the

observe two cycles of the wave shape.

here. This will depend on the number

bedue

pos-

operating

of

of later triangle codes.

bear in mind thatProduction changes on

on signal strength and component

of an oscilloscope

been obtained in the past.

is set at MAXIMUM CONTRAST.

to permit the serviceman to

from same wave shape shown

READINGS

SYMBOLTUBE PIN NUMBERS

PIN 1 PIN 2 PIN 3 PIN 4 PIN S PIN 6 PIN 7 PIN 11 PIN 9

V-1 MEG. 47 .02 Q '1311 I311 0_

V.2 I 47 0 0 I3K '13K 0

94 0 In .02 0 1311 I3K 0

7-4 .02 I MEG. 6 0 150K 0 4.741

V-5 1 MEG.CONTRAST

0 to 130 .02 0 221( I3K CONTRAST0 to 13K

- - -:1 14 MEG. 0 0 .02 '1311 1311 367:

' 4; 0 0 .02 931- Crv-11

V.9 10 MEG.1001(

0

00

N-----.02

TOOKTONTLS MEG. 13 MEG. 23316

V-10 N.C. .04 16.511 I6.511 4700V. CONTROL

0 to 210K 0 470

9.11 14.7K 0 .03 02 5.511 2.3 MEG. 0

220 264K 100K 0 0 11116 330K 4.70 .02

V -I3 2.4 MEG. 3711 I.2KHORIZ. HOLD

CONTROL100K -140K

4400 1.20 .02 0

V.14 N.C. 0PLATE100 .22K 476K 100 .02 '2241CAP OF

11063011

9.15 PINS 2 %ND 7 INFINITE PLATE 1011

V-16 220 N.C. 3211 N.C. 140 N.C. .05 0NAGIGTUSED

V-10 163K 2.2 MEGFRINGE

COMPENSATOROFF IRK

0 0 2.2 MEG. 470K FILAMENT

--.1

VI0 1001C 16.10 2.2KVERT. HOLD

CONTROL020 to LK

VERT. SIZECONTROL1.S MEG. to3.2 MEG.

2.2k .03 0

V.19 N.C. 0 14.20 14.3K 2.5 MEG. N.C. .02

LIN.CONTROL470

0 to5.40

-_VERT.

N.C. I4 1( N.C. N.C. 11,C, 11 1(N.C.IS140 N.C. 15 6.5 N.C. 141(

V..,11, Room... - 9.11 omit motor omlos (*loot 30 soyoo1a1.

V-24

PIN 1 PIN 2 PIN 10 PIN II PIN 12

0 0 112011

BRIGHTNESSCONTROL

22011 to 2400to Y2OK

.02

56


GENERAL ELECTRIC("F" SERIES CHASSIS)

Models 17C127, 17T15-17, 21C114 -C115 -C116 -C117 -C11921C120 -C121, 21110 -T11 -T12 -T14 -T15 -T19

UHF -17715, UHF -17T17, UHF -17C127, UHF -21C115, UHF -21C116,UHF -21C117, UHF -21C119, UHF -21C120, UHF -21C121, UHF -21T10,

UHF -21711, UHF -21T12, UHF -21719.

These receivers are 12 -channel models, into some of which theGeneral Electric model UHF -70, UHF -80 or UHF -90 tuner hasbeen installed.

These models are UL listed and incorporate 18 tubes and 4rectifiers (two power rectifiers and one high -voltage rectifier anda crystal diode). Receivers equipped with a UHF tuner unitcontain two additional tubes and one additional crystal diode.

(Service material on pages 57 to 62.)HORIZONTAL STABILIZER COIL-The coil, L251, should be adjustedso that the horizontal sync will remain locked over the entirerange of the horizontal hold control, R264. Also, the "pull -in"range of sync should be evenly distributed on each end of thehorizontal hold control range. This may be checked by switchingoff and on a station and observing the "pull -in" ability at dif-ferent settings of the control.

In order to adjust the coil properly follow the given procedure:1. Remove tube V106. Tune in a very weak television signal.2. Short circuit terminals of stabilizer coil, L251.3. Adjust horizontal hold control, R264, to bring received

picture closely into sync.4. Remove short circuit from across terminals of L251.5. Tune the stabilizer coil to bring picture back into a closely

synced condition. The stabilizer coil will tune to two positionswhich will bring the picture into sync. The correct position is theone with the core almost all the way into the coil.

6. Replace tube V106; check lock -in ability of horizontal syncon available channels.

It is absolutely essential that the stabilizer coil and the hori-zontal hold control be correctly adjusted, and once adjusted, beleft alone.

It should be noted that in some receivers the stabilizer coil hasbeen relocated and is available at the top rear of the chassis.

To Remove Safety Glass

MODELS 17715, 21110-T11.112I. Remove the two buttons holding the corner brackets, see

Fig. 10.2. Unscrew the two screws securing the corner brackets to the

cabinet and remove brackets.3. Tilt top of safety glass away from cabinet and lift glass out

of the bottom slots. To replace safety glass, use above order inreverse.

SCREW

BUT TON

CORNERBRACKET

CUSHION

GLASSY

CABINET

MTG. BOLTSORRAnET

PICTURE TUBEROD

TUBE MTG.CUSHION

PICTURE TUBESTRAP

MOUNTING WIT*TSn Tzw=m" "

ROD BRACKET*TUBE MIS CUSH ON*

FOCUS UNIT DISC

YOKE MOUNT ASSEMBLY

FOCUS UNIT AN NUTLOOSEN NUTS TO CENTER uNIADJUST SO TR, DISTRNCEBETWEEN FOCUS UNITAN. YORE FLANGE IS 2 iN

ICTURE TUBEROD

POWER TR ANSE

PRIMARY POWERP FUSE COVER .7

ROD NUT

ROD NUT

Z711ZY'RICTURE TUBE

YOKECONNECTOR

311SPREE BOLT

NUTaAUG

FOR NOCE, ,TiO, Tv B I, ONLY

AREACONTROL

HORIZONTALSTABILI ZER

COIL

FASTENING BOLTS*

MOUNTING NUT *

Tx: zmw cc

ROD BRACKET*

TUBE MTG CUSHION

PICTURE TUBE ROD

PICTURE TUBE SOCKET

ION TRAPROTATE v( OKRApp

Raw°, NEC. SNA00.

NU ANODEONNEC TOR

itsCLAMP RINGEXTENSIONNUT

PICTURE TUBE

HIGH- VOLTAGECOMPARTMENT

HORZONTALLINEARITYL253

R207 R211

O 0HEIGHT VERT

LIN

Chassis and Picture Tube Assembly (External Magnetic Focus)MOUNTING PUT

Tan 'zzirJ.44,

TUBE MTG CUSH

DEFLECTIONYOKE

TUBE MOUNT ASSEMBLY

PICTURECENTERING UNIT

VERTLu.NIENVED

UXISEN OAK T I

tnrtIRIET e

Egyar,zROTATE MAGNETMORO NOPCATEDANS

TUBE RIG CUSHION

YOKE CLAMP RINGWING NUTLOOSEN A. TURN Yr.TO CENTER NCTURE

NV ANODECONNECTOR

PICTURE TUBESOCKET

FOCUS CABLECONNECTED TO PIN 6 OFPTURE TUBE SOCKETFOR BEST FOCUS CONNECTTE, ['THEIR CHASSIS,. BOOST

Fig. 10. Deka of Picture Tube Mown (Models 17715, 21T10 -T11 -T12) Chassis and Pkture Tube Assembly (Electrostatic Picture Tube)

57


GENERAL ELECTRIC

VIDEO I -F ALIGNMENTThe following alignment data is divided into two separate pro-

cedures. Because of the large trap attenuation, the conventionalmethod of sweep observation of these traps sometimes becomesdifficult. Hence all traps should be pretuned by the applicationof an amplitude -modulated signal and then adjusted for minimumsignal output.

The second portion of this procedure involves the shaping ofthe i-f response curve in the conventional manner by the ap-plication of a sweep generator signal. During this procedure ob-serve the usual precautions regarding warm-up time, equipmentcable lead dress and generator output cable termination.

ST- 5AMARKERGEN.

SWEEP OUTPUTTO MARKER

0101CHANNEL 12

STEP I

47-1'

-n1

OUTPUT(CO -AX LINE)

F

FILTER

OUTPUT TO VERT.OF COPE

ST- 2ASCOPE

HOR. SWEEP VOLTAGETO SCOPE

RESPONSEUNSHIELDED PAIR

FROM RECEIVER

AT TENuATOR

Fig. 20. I -F Sweep Equipment Connection

0103CHANNEL II

STEP I

0105

T 01

CII5FINE TUNINGCONTROL

V101 TI ST V102MUT R -F POINT I CONY OSC

Fig. 28. Top View of R -F Tuner, RJX-057 J002UNE POWER

V102 V1016.16 61106

SIGNAL LEAD

GROUND LEAD

CHANNEL 6 RESISTORSCHANNEL 13 EACH 120 OHMS

Fig. 24. Oscillator Adjustments

COW/ PLATECONV L103

(TOP)

"F" Series, Continued

ANTENNA CONNECTION

TRAP ALIGNMENTGENERAL:

As noted above, an AM signal is required for trap alignment.In many cases, the technician will have a suitable AM signalgenerator available. It should cover the range of 40.0 to 48megacycles at fundamental frequency, with available internal400 -cycle modulation. When this type of signal is used, the trapsshould be adjusted for minimum 400 -cycle signal as observed onthe oscilloscope.

Users of General Electric sweep alignment equipment may ob-tain the required amplitude -modulated carrier frequencies by asimple manipulation of the equipment controls

Those technicians who do not have either of the above equip-ment available are advised to omit the trap alignment procedure.With the exception of the video amplifier 4.5 mc trap L156, thetraps will not become seriously misaligned due to tube changes.The above -mentioned 4.5 mc trap may be sweep -aligned, ifdesired, in which case a 4.5 mc sweep signal should be used instep 2, of the alignment chart. The trap may then be tuned tominimum response at 4.5 mc, which should be crystal markercalibrated.

NOTES:

1. Allow receiver and alignment equipment to warm up for15 minutes before proceeding.

2. Set channel selector switch to Channel 11 position. Turnthe fine-tuning control fully clockwise.

3. Turn the volume control and the area control fully counter-clockwise. Turn the picture contrast control fully clockwise.

4. Observe alignment wave forms at test point V (picturetube).

5. Remove V106 and V113 during alignment.

500 MMFTEST POINT ...1

L '52(SOTTO

4i 2SMC

eTRAP

BOTTOM)

T152(BOTTOM)

TORECEIVER

L1534125 MC

0TRAP

(BOTTOM)

ST, ()IDEO

®18(IT TO,

2NO VIDEO

3R0 VIDEO T

TIS3(BOTTOM)

L 156(BOTTOM)

o

4 5MCTRAP

VIDEOAMP

IN64

TO VERTICALINPUT OF SCOPE

Fig. 33. Detector Network

RATIO SET8 1ST AUDIO

SECDOR

(BOTTOM)

AUDIO I -FLIMITER

PRI"°1 ITOPI

'SEC(BOTTOM)

V 116 AUADIOpi F

L251MORI

STASILIZCOIL

AREACONTROL

RIBS

SYNC AMP15 NOISE

CANCELLER

AUDIOOUTPUT

VERTOUT PUT

VERTOSC

IO

CLIPPERAFC DE T

U

HORIZONTALMULTI -VIBRATOR

WIDTHL252 ETIFT.SL IN.

R264MORI-NOLO

CONTROL

SIGN VOLTAGERECTIFIER

HORIZONTALOUTPUT

VERT VERTS1Z E L IN

iliggToRt; ""3RD RI

VH4'4341

PER

Fig. 32. Tube and Trimmer Location

58

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONGENERAL ELECTRIC "F" Series RECEIVER ALIGNMENT (Cont'd)

TRAP ALIGNMENT CHART

STEPAM-GENERATOR

INPUT POINTAM-GENERATOR

FREQUENCYADJUST FOR

MINIMUM OUTPUTREMARKS

1 Test Point I

(R-F Tuner Unit)

See Fig. 28

47.25 mc L151May require maximum oscillo-scope vertical gain.

41.25 mc L153

2 Test Point IV(Diode Load)

4.5 mc L156 Connect detector network be -tween oscilloscope input andand receiver test point V asshown in Fig. 33.

I -F SYSTEM SWEEP ALIGNMENT 4. Note that theGENERAL:

reference point. Maintainthat the baseline to

After the traps have been set at their proper frequencies thei-f curve may be shaped. PRE -PEAKING:

The following procedure requires the use of a simple sweep Should difficultysignal coupling jig as depicted in Fig. 24. This device is made i-f response, the tuningfrom a tube shield cut in two halves, between which are soldered If the coils are eachtwo 120 -ohm resistors. The shield is placed over the 6J6 oscillator an over-all i-f responseconverter tube during the i-f alignment and hence provides loose proper curve willcapacitive coupling to the 6J6 i-f plate circuit. The resistors per- method may be usedform the dual function of supporting the upper half -shield and This peaking mayterminating the sweep output cable. The generator cable shield for setting the trapsshould be connected to the lower half shield, and the "signal" ing the coils for maximumlead connected to the upper half -shield.

NOTES:

I. Turn picture contrast control to minimum.2. Observe sweep waveform at test point III through a 10,000-

ohm resistor. Oscilloscope should be calibrated so that h -voltsignal will provide 2 -inch vertical deflection.

3. Apply a negative 5 -volt battery bias voltage to test pointVIII. Connect positive lead of battery to chassis.

VIDEO I -F ALIGNMENT CHART

following procedure uses 45.0the sweep generator

45 mc marker amplitude

be experienced in obtainingof the individual coils

peaked at the below -specifiedcurve which closely

be achieved. After thisto thus permit proper

be done by using an AM signalor the sweep method may

amplitude at the desired

mc as the 100%output level so

equals two inches.

the proper videomay be checked.

frequencies,approximates the

is done, the sweepfinal curve shaping.

as prescribedbe used by adjust -

marker points.

PEAKING FREQUENCIES

L103-44.15 mcL152-44.15 mcT153-44.15 mcT151-45.25 mcT152-42.9 mc

CONNECT SWEEPGENERATOR

ADJUST DESIRED RESPONSE REMARKS

Into alignment shield jigand r -f tuner chassis, seeFig. 24

Peak T153, L103L152 at 44.15 mcT152 set 42.5 mc La 55%T151 set 45.75 mc @, 40%

_140%

lio%00% 45.0 MC

42.5 MC 55%45.75 MC

4125MC K... 47 25MC

T153, L103 and L152 should bereadjusted slightly, if necessary,to shape peak region of curve asshown. Peak of curve may fallanywhere between the limits of110% and 140% of 45 mc 100%reference point.

AUDLO I -F ALIGNMENT 2. Step 3 below requires a meter connection to the electricalNOTES: midpoint of the ratio detector load circuit. To do this, connect

1. Tune in a television signal. This will provide a 4.5 mc signal two 100,000 -ohm resistors in series between V118A (6T8) pin 2source for audio i-f alignment. Keep the volume control turned and chassis. These two resistors should be chosen, as accuratelydown unless the speaker is connected. as possible, for equal resistance.

AUDIO I -F ALIGNMENT CHART

STEPCONNECT VTVM OR

20,000 OHMS/VOLTMETER ADJUSTMETER

INDICATIONREMARKS

1 To Test Point VI and chassis T301 (top and bot-torn core*)

Adjust for maximumdeflection.

Voltage to be read is negativewith respect to chassis.

2 V118A, pin 2 and chassis T302 primary (bot-tom core)

3 Between Test Point VII andcenter of two 100,000 -ohm re-sistors, see note 2.

T302 secondary (topcore).

Adjust for zero voltsd -c output

Repeat steps 1, 2 and 3 to assureproper final adjustment.

*Some receivers use only one core.

59

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONGENERAL ELECTRIC "F" Series Circuit Diagram

ROOST

60

0 © 0

YON

awl". NIL.

Vertical Output Blanking Circuit & Pix Tube Circuit (Mid & Late Production)

B+250V

R201 C202 R202

821,00 82KTO PINT -c201OF V107 .T:00iMF

0254

C203470

VIDEODET

LI5 RI83470K

TEST POINT 1/2W3ZIff

AccI -F

AGCR -F TUNE

R22I

)grET. 3 MEG

R220V110 4.7 MEG

6.15VERT. OSC C206

R204

27K1 OLOK OR

VERT.HOLDR2051256

R208

0 IMFOR

TAM56W

C207

.022MF

TO R181

Vertical Six. Circuit (Mid & Late Production)

Wiring Diagram for T153

C I65

C153.05 AAF

RI806801(

RI842201(

CI71.2

RI 88AREACONTROL2MEG

253470K

R254

C253470

Late Production AGC Circuit

V107ASYNC

CLIPPER

VIII6AH4GT

VERT. OUTP.

TO T2015 B C208

R210330

VERT.LIN.

R211OK

C401100 .9-61F I

75V _

1401

1403YOKE PLUGINTERLOCK

54014

F401FUSE4 AMP

117 V

R401

402 30K

r(k14131

1170-60

OUTPUTCIRCUITSCULTS OFR -F TuNER RJK052-057VIO2Aj2 -6J6

CONY.

T1TO OSCI

*TESTI POINT

IO

+250V

it

2

44-4IL.3 6.3VAC404I 4

5800--10V/TUNER AGC

B + BOOST piPliTCEIWITA SLF3-.E UPCRFqx017,V102A

1/2 12AT7CON( 1

VI20 V1215U46 51.14GRECT, RECT.

6 4

0103 V104 6C6CB6 6C86

3 4 3 4

41.25 MCTRAP

CI566

CI I

C152

T ' 28152

LI51 .47.25 MC 1,00K

TRAP nA-1-

CI74-

IZIK800

13RD 81 TEST POINT

V103 V 1046C861ST IrF 2

6ND C136

220V T151 200V

R15356

TESTPOINT II

TO 0151

+250VFIL.6.3V AC

AGO

63V2 BOVL

RI54 +160V

CIIRT41(

J402FOR UHF ONLY)

AGC

M2MF

R402

3000WW

R405 AUDIO OUTPU680 C4018 2W t. 30MF

8+ 260 V - 350Vita

L401580

470 ." .c..02850 D

M.,2, 2W -140MFRF

CAOI A5.50V-L350V 350V

5 V i0 vin V 19 V107 vi12 VII5 Via6AU6

R403

6 6J5 6AHOGT 6V6GT 12AT7 12AU7 6A04

©ws9 4 S(47 1492

3C4800

HEAD

1403YOKE PLUS

TERLOCKF401FUSE4 AMP

5401

070-40',

1401

END FIL. UHF FIL.

V120 VI215U40 WIGAEU REV'

V106 V118 4108 409 0116 V11312AT7 676 6407 PIK 6CB6 6806

(OR 6CL6)

NOTE Al 8275 MAY BE REMOVED TO EXTENDRANGE OF SYNC CONTROL.

+160V

+225V

B+260V

1-2 OV

10 L40i

ALL RESISTANCES IN OHMS.ALL CAPACITANCES IN MMFD UNLESS

OTHERWISE NOTED.6.1000MEGH,000,000

(1ST P.hNOICATES 1ST PRODUCTION.(2110P)INDICATES 2ND PRODUCTION.(3ROP.I INDICATES 3RD PRODUCTION.

DOTTED UNES INDICATE LATERPRODUCTIONS.CIRCLED NUMBERS AT YOKE REFERTO PIN CONNECTIONS ON YOKE PLUG.

3

* SCOPE SYNCED AT 1/2 VERT. FREQUENCY.** SCOPE SYNCED AT 1/2 HORIZ. FREQUENCY.

WAVE SHAPES TAKEN WITH NORMAL CONTROLSETTINGS a NORMAL SIGNAL APPLIED.

VOLTAGE MEASUREMENTS ARE IN RESPECT TOCHASSIS WITH A 20,000 0/vOLT METER,WITH CONTROLS SET FOP NORMALOPERATION, NO SIGNAL APPLIED.

A MEASURED WITH VTVMENCIRCLED LETTERS REFER TO TERMINALBOARDS OF TEST POINT DIAGRAM......6.3vAC to rum PLS.

.6.3VAG TO TUBE FLS.

Late Prod. Power Transformer Wiring

8180

2.2 NEC

(saR179!MEG 8188

R177470/K AREA

2 MEG

CONTROL

00V

TESTPOINT

C252 14'0C3

.0047 ..254i --47250MF 470K

-2.1V

V 1166CB6

AUDIO I -F AMR

210V

NB

165V

630218K

C302T1300

60


1152

8157III

C157800 B+ 260V

CI59800

V1056C863R0 I -F

0

CI60

815800

RI59

18K

B+260V

V107A255 1/2 I2AT 7/OK YNC. CLIP

1

F4 5V

T301TRANS.4.5 MC

1

II 4

iT8

3L _

03035000

8+26

R3034700

1W

V

R201

T*

POINT

Y15I LI571153 - 1086

81604700

I W

M 810602

8 214 R207 R2I5

2.7MEG VERT. 2 G

V110625

ERT. OSC.

VIO7B1/2 12417

PHASE OFT.-I.75V

C254

180

V1176 AU6

LIMITER

R305100K

TESTPOINT

R2522.2K

R3064706

B+2

c165 POINTTST

451.1CTRAP

I MEG OR1.5 MEG

R208100K

N.V.F 27V cer

C207

.022MF

C204.IMF

.5.3V8204100K

R2051256

VERTHOLD

R166686 OR33K

8209

MEG

50V

+ 250V 4c259.0039a MF

C23056

MF_2

V106A V10681/2 12AT7SYNC. AMPL.

I/2 I 2AT 7NOISE CANCL

C166.2MF

B +BOOST (PIN IO-y109)

V III6AH4GT

VERT. OUTPUT

.022 MF

VERT.LIN.

82628200

R260 I

I MEG 560

235VC208-1_

047

909 -30V

C402R217 3511

30 MFR210220

330 350V 414_1_+

RED 3C40ID - 82I 2 I-

I100MF 470

411 75 V

GENERAL ELECTRIC "F" Series

V1086AG7 2

0168 VIDEO AMPL.

.05WR1682206

CONTRAST

81692.2 MEG.

B +260V

r GREEN 7

82162200

**

R I 7 11100V

225VC170

L I 58 IMF TESTPOINT 35-115V

30001

- 350V

8171IRK2W

300V

270 pH

RI 72

WW

8173826

D201DEFT. YOKE

3511.

2

8261826

3 8.2V

C257 275 328264.001220K...: 200K

HORR259 MF 0258 ' HOLD826 05MF__ __SEE NOTE A

L251HOR.STAB.

190V

V 11212AU7HOR. M.V.

5V

1302

RA-T10-0-ETTII TRANS. 1

27K 030725000

RATIO DET.

R257

0

20V

R26347K

200/ R2676800

R266

0255 -560

B +260V

6806HOR. OUT.

R269330

R270150

8268 484706

V 118 A 3 V 118B1/2 678 TEST

830915 MEG (maw p) 1/4 6T8

POINT

R31122K F .1 CONTROL

C312 VOLUME

AUDIO AMP.

310

C.C1 Z.°°CZft ;3201IST.

C309_4

33K

fC 317

.01MF

GONSkES- ONLY

R 3I 4470K

0315

C263.IMF

V

4. C4020- 10M F

25 V

R27IISK2W

B+260V

VII96 V6 GT

AUDIO OUTP.

6316 23008MF

R175100K

BRIGHTNESS

R 181 Ri 7 6MEG 100K

YOKECONN.

:1529r1

6265

7

+255V

1000V

8315

_10_0_0_;

(3RDR313 14470K

+240V

/ RED260V

R3174702W

V I 09PICTURE TUBE1701.4.21Ep4-4

8+260V

C2.04766 MFT

V 114183

H.V. RECT.

83972.2K(3ROP)

8274

2206

.-16KV

VI156A54

DAMPER

HORZ.LIN.0268

01MF T8+ BOOST

B+ 260V

LOUDSPEAKER

Schematic Diagram with Waveshapes and Voltages

61

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONGENERAL ELECTRIC "F" Series TROUBLE SHOOTING (Cont'd)

SYMPTOM CHECK FOR

DEFECTS OF THE SYNC SECTION

A. Weak or no horizontal sync; vertical 1. Sync amplitude at input to discriminator tube, V107Bsync, picture and sound satisfactory 2. Defective multivibrator components, C260, R263, R264 and R266

3. Leaky or shorted capacitor, C2604. Wave form feedback components, R257, R267, C255, C2625. Defective L2516. Open C259 or R260

B. Weak or no composite sync, otherwise 1. Defective coupling capacitor, C252 or C253picture and sound normal 2. Incorrect value of plate resistor, R255 or R256

3. Insufficient amplitude of composite signal applied to sync amplifier from video de-tector; check video detector circuit

C. No vertical sync, horizontal sync satis- 1. Sync pulse at input of vert. oscillator, check integrator circuitfactory 2. Vertical oscillator frequency, if far off from 60 cps, check vertical oscillator com-

ponents such as C207, R204, R209 and R2183. Leakage in feedback capacitor, C206

D. Picture displaced to left, right edgewavy

1. Open or low value of capacitor, C253

E. "Gear Tooth" effect 1. Open or low value capacity of C2582. Open or high resistance of R261

F. Noise "tearing" picture (noise inverter 1. Low value, R169failure) 2. Open C167.

3. Open or high value, R167

G. Weak composite sync (attributable to 1. Low value of R167excessive noise inverter clipping) 2. Leaky or shorted C167

DEFECTS OF THE HORIZONTAL DEFLECTION CIRCUITS

A. Too great sweep width, reception nor- 1. Open width control coil (shunt section)mal otherwise 2. Open winding between width coil shunt section taps on horizontal output trans-

former, T251

B. Inadequate picture width 1. Correct waveshape and amplitude of input "drive" voltage at grid of V1132. Leaky capacitor C2653. Shorted width control L252 shunt section or defective deflection coil, D2514. Defective output transformer T251 shorted turns or arc -over5. Low emission of tube, V113, V1156. Low B+ voltage to tubes V112, V113

C. Single vertical line in center, sound nor- 1. Open horizontal deflection coils, D251mal 2. Open yoke plug connection

3. Open width coil (series section)

D. Poor horizontal linearity 1. Shorted linearity control2. Defective yoke, D2513. Defective capacitors C265, C266

DEFECTS OF THE VERTICAL DEFLECTION CIRCUIT

A. Poor vertical linearity, inadequate 1. Low emission of sweep output tube, V111height 2. Improper grid input "drive" voltage at V111

3. Defective sweep output transformer, T2014. Low B+ voltage to sweep output tube V1115. Low value of cathode capacitor, C401D

B. Inadequate picture height 1. Rise in resistance value of vert. oscillator plate resistor, R206 or R2152. Incorrect value of plate voltage on output tube, V1113. Low value capacitor in cathode of vert. output tube, C401D (This often results in

poor linearity)4. Weak vertical deflection tube, V110 or V111

C. No vertical deflection 1. Open vertical deflection coils, D2012. Defective sweep output transformer, T2013. Shorted capacitor C2054. Poor contacts in yoke plug

D. Poor vertical linearity, height satisfac- 1. Low value capacitor, C205tory 2. Vertical output tube, V111

62


GENERAL ELECTRIC

The "G", "J", and "K" Line setsare similar to "F" Series and toeach other. For circuit diagramof "G" Line see pages 64-65, for"J" pages 66-67, and "K" page 68.

"G" Line, Models 17T20, 21C103,21C104 21T22, 21T23, 21T24, 21T25."J" Line, Models 21C350, 21C351,21T30, and 21T31."K" Line, Models 17T14, 17T15,17T16, 21T17, and 21T18.

CSC

CONY PLATE U3544 I5MC

PF AMP

VHF

L_SEE NOTE

CONY

UHF

NOTETHESE TUBES ARE NOTINTERCHANGEABLEREPLACE WITH SAME TUBETYPE AS INSTALLED INFACTORY

T4 01ROWER TRANS.

LI51

LI52.LINKSEC.

T152

2NO.PF(RIDE())

L1.56

S MCTRAP

LI53SSMCTRAP -

c;L16I34.25MC

IST YIDE0 ,T15IITT I -FIDEO)

I- F AMP2ND VIDEO

1-F AMP3RD VIDEO

(2.Ti533RDVIDEO)

RIO. AMP

RECT

RATA xi, ALAMP 5 DELAYED AGC

302RATIO DET

SEC.

LIMITER

<>T3C4.5 MLFm

ALA I -F AMPNOISE CANC.

SYNC AMPHORZ BLANKING

PELT

AUDIO OUT

SYNC PHASESPL-ITTER

SYNCoLIPPER4:022 PHASE DET

HORZ REACTNORZ OSC.

HORZ. DISCHARGEAEC KEYER

F25IFUSE 3/RAMP

HORZ OUT

Location of tubes and adjustments in "J" Line sets.

OOcr

(11):6=

ti

NO_J 2

63


SCREW

BUTTON

CORNERBRACKET

CUSHIONS

SAFETYGLASS

GENERAL ELECTRIC "G" Line, Models 17T20, 21C 103, 21C 104, 21T22 to 21T25

CLEARANCE

CABINET

TUBE HARNESSMTG. BOLTS

MCTRURE TUBEOD

TUBE HARNESSASSEMBLY

DETAIL OF PICTURE TUBE MOUNT(PLASTIC MODELS)

PICTURE TUBE REMOVAL AND INSTALLATION

Details regarding picture tube rods, tube holder,focus unit mounting hardware and ion trap do notapply where internal magnetic focus tubes are use&The shunt focus control and deflection yoke withpicture centering assembly are simply withdrawnover the neck of the I.M.F. tube-- the yoke clamp 000wing nut is loosened to allow removal of the de- 3.3

flection yoke.

Removal Of Picture Tube

ASSEMBLIES IN PLASTIC CABINET:1. Remove the chassis.2. Lay cabinet, face downward, on

scratching surface.3. Remove ion trap.

. Remove the two focus unit mountingslide focus unit off tube neck.

5. Loosen yoke clamp ring wingnut andflection yoke off tube neck.

6. Loosen the four picture tube rod nuts.move rods, and picture tube holder with focusunit mount.

7. Remove mounting nuts and washers securing tubeharness assembly at the bottom and in the twoupper inside corners of the cabinet.

8. Carefully remove tube and harness assemblyfrom cabinet. Lay tube, face downward, on

bench.9. Loosen spade bolt nut and lift tube from har-

ness assembly.

ASSEMBLIES IN WOOD CABINET:

C301120 -r

O

11

I

padded non -

nuts and

slide de-

Re -

1. Use same procedure of steps 1 through 6 des-cribed above for tube assemblies in plasticcabinets. Then continue disassembly as follows.

2. Remove Phillips screws at lower corners of pic-ture mask. Move tube and mask slightly towardbottom of cabinet to free mask from cabinettop rail. Remove and place tube, face downwardon bench.Loosen spade bolt nut and lift tube from har-ness strap assembly.

To reinstall a picture tube the applicable(plastic or wood cabinet) tube removal instructionprocedures may be applied in reverse.

rVHF TUNER RJX-059 OR RJX -0623P VIEW)

OUTPUT CIRCUIT

T101

BRN. ORANGE RED ORANGE/FL. +130V +250V WHITE

+130

HITE H E AGO

V1146AU6

AUDIO I -F

I 7300

70V cum)10

I OV270NA

7 1".....6C00300211

6115000

I

R3Il470

C312

R164

B+ TO TESTUHF NT

1130V VPOS)

130V UHF P0s)II

VI 156AL5

RATA DET.

R303

V1036096

IST VIDEO I- F

1.4V

168Doc)

V116

V TEST POINTEAV6AUDIO AMP

0307.01

"%WI6305 I

oa 1

-.

R304 03

500K -R307 _.21410K

Ma11 R306

6V &am

.8V 11:R313

CONSOIFS''.33KR33300

130

1

:WLY

--"zzR3

B+275V

R3084701(

-1V

T150

ase800

DISTANT

R179

IK

0174

V117

AUDIO OUTPUT

0310

=.00221000V

030p0V01

OV

275V

7301

B+260V25V

LOW B+I30V

R31.IM

* SCOPE SYNCED AT 1/2 VERT. FREQUENCY.** SCOPE SYNCED AT 1/2 HOME. FREQUENCY.

WAVE SHAPES TAKEN WITH NORMAL CONTROLSETTINGS B NORMAL SIGNAL APPLIED.

VOLTAGE MEASUREMENTS ARE IN RESPECTTO CHASSIS WITH A 200000/VOLT METERWITH CONTROLS SET FOR NORMALOPERATION,NO SIGNAL APPLIED.

A MEASURED WITH VTVM. VARIES WITH CONTRAST CONTROL,

BLACK T400 YELLOWS YELLOW

V1185U4G

EARLY PROD!.SETS ;24K

2W1

L40014

TD4o0AollBOMF

TTIIPOINT

R401 -H3OV

330 8402.T.800

+1C400CR403 .100'FV

3 ,U.* 10403

V113 VIII VII

RED

V108 V109 VI

GRUA

6AX4GT

311'1

I2AT7 12AU7

14011

I

TO R -F TUNER

p. -t-I30V

TO+R2-;0TVUNER

I04000a+260V

_= 350V

4V105 ev119 6 V106 M

4,5360436 6056

ThREEN=_CR TUBE I2BY _6cS 6

-110001 CM'

111. +275V

TO R -FTUNER FL.

VI 61 c4 04M. BOO

TO UHF6AV6 TUNER Fl L.

6AU6 1 GALS

V103

6C B6 **

24V

64


V1046286

2ND VIDEO I -F

2213c .755,

2018

)V

R167Kvv..4706

LOCAL --

2251

801(

33 K

R202IIM

+130V

I 0201.05

R200

1151

RI5733K1W

628631313 VIDEO 1-F

+275V

V1076 CS6

NOISE CANCEL ER,CLIPPER

TEST

Y151

71520161

R1606 8KIW

RI6847K

V105 IN65 12169 101655 =800

Y150 L155

R161 L154

3.3K 330 Ph

iT,KT mqAir"

3VI I n 33V

V106 L171 L172128Y7VIDEO AMP

LI70 2170-6-, II 0 0

680, .05

470K _L CL66=80C

V108A12AU7

PHASE SPLITTER

9170270K

7 228173

;927V

157 = LU4330,h

PICTURECONTROL

V109A1/2 12897VERT.OSC

TESTNT IY

1804h270K OV

+130V 1-275V 1-130V

VERTSIZER232

636N 30V

2203228207

R32300 245V .005 /7

2225

77

R227 R228.`, 022321

A.14700047

*--1( wv, -...,..1 i

336 82K 6228 A:0

,X22°2 55V

2V,, 20 . R2 2, ,Cn R 22 56 I5K ''''' 50viK

R25047K

..7.23i26-.001 3.5V 3

4*§/1 .00 '6

R2324

1755 I2202272

I(--- 82K =R209 10K I-2472029

6 2, 8210 --T .0

22201% R203 126 = 4231.,230 4R 2717

16K,2W 2WVERT.506 4235ILIC

DISTANT

V10981/2 12887

VERT. OUTPUT

R207 R208

IOM 820K* *

7 Bt275V4 5V

V1088I/212AU7

PHASE DE T.

A 15.7VR252

424125V310K

R256

8254

150K

12M R256 -1_100K "-HORIZ.12f0

12252T750

R257

VI I 0I2AT7

HORZ.OSC.

L250TEST HORIZ.STAB.POINT

2000 120K

f.0 2552

C253 =.200-=-

UNLESS OTHERWISE NOTEDCAPACITORS MORE THAN!. MMFCAPACITORS LESS THAN I MERESISTORS ARE I/2 WATTK 1000 M 1,000,000

257.510

...I 826039K

+130V 4

VIII6 BO 6 GT

HORZ. OUTPUT

1-2 75V

N58

01

R264 R266I2K v***33042V

R2C259 im

65I I5.5V 620

R263

C261

1100 7°K

12V

B -I -275V

1903YOKE

INTERLOC

I55V8267

I5K2W

-6260105

R2362K VERT

LIN

L 254DIU

10 200,,P (3

2262 I HORIZ. g IaZ240

5611COILS m

5611L L252 27(15OHORiZ 8001

000

MLW,2D5T,.

68673R2

61- "'" """

VII9170 P42IARP421 AR P4A

OR212 P48

6+ BOOST 500v

YELLOW

R268Ny.

3.3

2176

1

RI782.2

1050V

R238 500V

476,2W

2265

.068I(

600V

B+ BOOST 5005

VI 12I B3GT

HV RECT.

R271

;Tic

VII36AX4 GT

DAMPER

--10.6+ 275V

65


GENERAL ELECTRIC "J" Line, Models 21C350, 21C351, 21T30, and 21T31

r VHF TUNER RJX-062 (TOP VIEW) 7OUTPUT CIRCUIT L.I35

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WAVE SHAPES TAKEN WITH NORMAL CONTROLSETTINGS & NORMAL SIGNAL APPLIED.

VOLTAGE MEASUREMENTS ARE IN RESPECTTO CHASSIS WITH A 20,000.0 VOLTMETER,WITH CONTROLS SET FOR NORMALOPERATION, NO SIGNAL APPLIED.

MEASURED WITH VTVM

VARIES WITH CONTRAST CONTROL.

T401

F401, FUSE4 AMP

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GENERAL ELECTRIC "J" Line, Models 21C350, 21C351, 21T30, and 21T31

V106 -A1/2 12AT7

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hallicrafter5CHASSIS A1600D

CHASSIS B1600D

*CHASSIS TYPE NUMBER MODELS CHASSIS MAY BE USED IN

A1600D 17T310W, 17T310M, 17T310B

B1600D 21T320W, 21T320M, 21T320B21K330M, 21K330B

The A1600D chassis differs from the B1600D circuit primarily in the deflection circuits. A 6CU6 is usedfor the horizontal output tube, a different vertical output transformer and deflection yoke are employed and a fewcomponents change in value. For full details consult horizontal and vertical output stages on the schematics,

- icor;2T,O oo m.000 31cm91_

I MFD CI61 1.01

D_2

.005MF -

R143Lira

11,W

D UE 1106 YELLOW/

C135.047MFD

5V1

_ro/ C135

.033V1 10A

MFD3VERT.

Y2128117VERT.

%)27,000

14I RI6613,3,000 RI67

8h9(3 tp 15/4000

C 10.1 3:61-4 33

30V.P-P

R159560

1.4v P -P N160ect000

F1161I5b

a_2sy, ,---

ii.------s,

, la- ,, 2 7MEG3 , ' V107A

F265N7GT7;11 1.63RIZ. AFC.

144 1 0145ilkI_

A.R162 R163 -"100,0008200

Part of circuit of A1600DShowing differences from B1600D circuit as printed on next two pages.

65v P -P

18,000

C1471220

1108

57.5"

1203PP

MF Dr

Hrv

1100P -P C1491--..).215vi

V107 El I 0I50_igawacr = 560Z. 090.

RI 70470,0001

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arm

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C

0

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18,000, 2WAniff.

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SEEN fa ;51TkJ"L107 -A

VERTDEF LYOKE

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4. 140 V

3 04

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C152 < a MFD

168CI51

22 MFD05RI7 3

7 7L10713HORIZ

DEFLYOKE

C154

47

Ei_W-r;

REMOVAL OF CHASSIS FROM CABINET

The chassis and chassis board are removable as one unit.

1. Remove the control knobs, the cabinet back, the antenna terminal strip, and the wires from the speaker.

2. Remove the two wood screws on the inside rear corners that hold the chassis board to the wood supports on thebottom of each side.

3. Remove the hex head screws and lockwashers that connect the cabinet to the base board along each side fromunderneath. Also remove the wood screw (two wood screws on 21" models) from the center front.

4. Lift the cabinet up and off the chassis board. (Continued on the next three pages.)

69

MOST -OFTEN -NEEDED MS TELEVISION SERVICING INFORMATION

PRIVASSOAS,

21" Tube Mounting1600D Chassis

C1024--4-1(470

1102

470K

C16350001000v-if-R 176

336lw

/7/7REAR TUBE CHASSIS

SUPPORT

P101

CA102

1152

7.25W

1 I

SWI

VIII T102

7 8

PIN 21109

CIO10 CLIP

MONTH'SCana

CONTR.PATO WI

TUNE.

IMF

NUR..SOCCET

V101

--c.tie 6086137 PIX. I -F

L101

VI ) / V2 \r A. 000/---:---3,-.. ,i-

'.6./6,

VHF R -F TUNER

ID2017

25.11FIC

HALLICRAFTERS, INC.

VHF

21" CHASSIS

B1600D

RUN 1

L10225.5NC

isov

2

R105 # R1062700 . 47

R104m4v1000

L160

57$

15K

004o.25v1Dg

DEPENDS ONSTRENGTH

SIGNAL

V102 L103 116086

242 PIK

1+14061

10R09

00R110

"7005*1000* IMFD tRin

47

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007

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0622.05

MFD

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220

vEL.

50." C132B 0.76 P -P

200MFD.

Abaft!

140 - 2mFD MFD 0.21 P -P

R FE - V2

4 3

I

0 0

I ..-r.

_Lv108

2 A 7 ).-

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_ _ PC101-1_I -1_0157 P178

T270 330K

I IC158I

Tfelo-

....L.CIS9

."T-25 241.

:

RI38820K

TUNER 55 v. PP

V 1 I

113_._

Id

NOTES:

I ALL vCUPGES MEASURED WITH AN ELECTRCNIS VOLTMETERCONNECTED FROM SOCKET LUG TO CHASSIS, 9EE FOOTNOTE

2 SUPPLY VCITAGE 117 VOLTS 60 CYCLE AC.

3. K 10004.ALL CAPACITANCE VALUE IN MMF ALL RESISTANCE

veLuES IN CHESS I.R1LESS OTHERWISE NOTED.

10,000

42 V-1

R175680K

V104BI'26AN8SYNC.

CLIPPER

11406,8K

1W

C13Q1_,7012_5 65

536. P-

[7;11;917922K

0141

,._NOV P -P

o VIC6B

37 v. P -P

V101 V102 V103

3/14 3/1, 4 ASL110

w '------ o_fr 0-01_..-:- CI55 - C156

I'MMFD MFD

' =

VIIO V109 Y107 YI06 V105 V104 6113

4 9 5 2/17 8'7 3/14 4/1S 4S 12/\1

*SomE vCUAGES AE PIRIPILE IvoLuon *gym *ERE REARM

WITH A NORMAL POVIRE 061 TIE NcTuRE TUBE AND THE CONTRAST

AND DRIGNINESS OCPHROL SET FOR 50 VOLTS PEAR TO PEAK ONTHE 0.1101001 (RN II) OF THE PiCTURF 1I.11F.S00111 SWAGE11:URINCEI 10i

TIOI

PIED 001

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- 1

2

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5

41

MOST -OFTEN -NEEDED 195 5 TELEVISION SERVICING INFORMATION

V10613846

LIMiTERDET

SALVOECTORASP_

1+261

RI32500

RI31 BUZZ183 CONTROL

_tALJ*v R134

470

L)06

s

024

C1231 MFD.-105/

1 -1;6 111.6K1W

CI251

TIS

Hallicrafters, Inc. Chassis B1600D

C1261I .000A

C127M4135 =330K12

02MFD

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426

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os

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711-iirfr0 Q.0 r

V104A80V P -P

VIDEO AWL.

L1090 OTPr6AN8

\MIM I

C115 33

:1516FD

2

R1201500CONTRASTCONTROL

R123 -I68,000

/R12239KIN

L105-

RI24

10K ,2WRI55-WA18K , IW

fTR

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our T106

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3

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33

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!WC. STOPG.HEIGHT

CONT.

756 P P

2

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OUTPUT

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10

71

n07-11107-A

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I DEFLI YOKE

R147750VERT.LIN.

+ 505V IGRN ;ORR

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OUTPUT

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s

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DIAPER

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T 09-I

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L107E140312DEFLYOKE

J.410VI -- c7c5

12.6104

( ZERO BEAM)

71


Hallicrafters Inc. Chassis A1600D and B1600D (continued)

LAYOUT OF CHASSIS

VERT »,

;HOLD

HORIZ.

r"" --HOLD

CONTRAS

STATIONSELECTOR

FINETUNING

VERT

HOLD

Nom2

HOLD

OFF -ON

yaw.

CONTRAST

AUDIO OUTPUTTI OS

OUTPUT

*.R1261410'

k...), BRIGHTNESSCONTROL

A A

v10825L6/GT

VI613C5

R FAMP

0 yi-ix9ERPLATE COIL

VHF TUNER

RI 5 2

AUDIOOUTPUT

VERTLINEARITY

CONTROL

TI02HEATERTRANSFORMER CENTERING

EARS

128H7

RI96

HEIGHTCONTROL

L101IF INPUT2 5.IMC

O

1ST IFAMP

VERT OSCVERT AMP

DEFLECTIONYOKE BRACKETWING SCREW

IL25.5MC

2ND IFAMP

0142Holuz.LOCKTRIMMER

L10322.9MCFRONT -COUPLINGREAR -TRAP

V1076SN7i

GT

AFC B HORI2OSC

0 6ANBVI TIO1

IF OUTPUT V.1,,,°4N.24. MC

CLIPPERSRO IF AMP

VIDEO DET

VIII6,404/

GT

NORiz DAMPER

T109NV TRANS

V1096806/

GT

RORIE OUTPUT

LIMITERDET

AUDIOAYR

L109SOUND

TAKE OFFTRANS

I FRONT-PRI)I REAR -SEC)

0

L106QUADRA TORE

COIL

a5MCSING

AMPLIFIE

Tube and Alignment Locations lr 1600D Chassis

Lll P101L

1101INPUT

251.

yYR7 OSCVERT AMP

P146

0cg4THT

CENTERINGEARS

0142KNIT LUCK

TRIMMER

DEFLECTIONYOKE BRACKETWING SCREW

Arc a HORIzoso

SOUND

L102 L 103 TmE oFF Lill

25.514c 22 9NC TRANS

ER., COUPLING I FRONT...11 0.RE -TRAP ,REAR.SECI VC6 SOUND

21.5 MC OURCO)

COUPLINGTRAMS

LICRD CS.VIDEO AMP a SYNC

F OUTPUT ISYNG Ampunot24 AMC CUPP.

SRO !TAMPMCDO OCT

SOUNDCOUPLING

TRANS

R132

RUZZCONTRO

DAMPER

T109 -INV TRANS

RORIE OUTPUT

L106RuADRATuRE

FAIL

TIORNow FRED

LIMITERDETECTOR6 ADDIO

AMP

0TIOI

A A

fAMTROU

Tube and Alignment Locations 21" 1600D Chassis

72


Circuit diagrampages, over.the page following

DEFL1CTFOSIYOKE

0

Chassis SeriesChassis SeriesChassis Series

is printed on theAlignment information

the circuit diagram.

1111111111111C11,111111111b

SERIES 123-17"0

SERIES 124-21"SERIES 124-2-21"

123, used in Models 78, 78A, 79.124, used in Models 81, 82, 83, 84, 85.124-2, used in Models 86, 88.

DEFLECTION YOKE ADJUSTMENT

next two 1. Loosen the wing thumb screw located at the top of theis on deflection yoke frame.

2. Check to see that the deflection yoke mounting bracketrubber cushions press firmly against the flare of thetube.

3. Press the yoke firmly against the flare of the tube.DEFLECTION YOKEWING SCREW 4. Rotate the yoke until the lines of the raster are hori-

zontal and squared with the picture mask, and tightenthe wing screw.

FOCUS COLINNS SCSI - --

RUSSEI CUSHION

I .. CENTERNN ONIC(NOT

XI: V USEDON ALL SETS)

m

68

egt0. (101.7 0 0

N

:srATZEDRTATKIEE

3. rlJ 0 01 :.

FOCUS COL

gn : @ ':''' @r , ,,, ......*

.

.

TUBE COMPLEMENT AND VOLTAGE CHART 4;::- :AM .....

SymbolTubeType Pin No. 1 Pin No. 2 Pin No. 3 Pin No. 4 Pin No. 5 Pin No. 6 Pin No. 7 Pin No. 8 Pin No. 9 NOTES FOR VOLTAGE CHART

VI 6807 165 -1 0 6.3AC 0 265 160 165 01. Tune to -

V2 616 75 135 6.3VAC 0 -3 to -5 -4 to -9 0 - - receiver unused chan. no signal applied.

V3 6CB6 -1 .55 0 6.3AC 100 100 0 - - 2. All front panel controls at maximum clockwise6.3AC 101 101 0

Position.V4

VS

6CB6

6AU6

-10

.55

0

0

0 6.3AC 102 102 1

--

-- 3. Screwdriver service adjustments - adjusted for

normal raster.6.3AC 0 0 0 -V6

V7

6A15

12BH7

0

152

-.750 0 6.3AC 6.3AC 57

-.35-.35

-0 - 4. Maintain line voltage at 117 volts A.C.

V8 6AU6 0 0 0 6.3AC 105 105 .9 - - 6. All voltage measured with V.T.V.M. unless other -V9 6T8 -.35 -1.7 -.35 6.3AC 0 0 0 -.35 40 wise specified.

VlO 6K6 NC 0 210 219 0 N.C. 6.3AC 14 - 6. Values shown are D.C. voltages measured fromVII 6SN7 0 28 2.4 28 74 28 6.3AC 0 - socket to ground unless otherwise specified.

V12 6C4 144 0 0 6.3AC 144 -34 0 - - 7. N.C. designates no connection.V13 6V6 NC 6.3AC 275 275 -24 - 0 5 - 8. A dash designates the non existence of socketV14 6SN7 -3.5 175 12 -65 188 0 0 6.3AC

con -nections.

V15 6AV5 -25 6.3AC 0 - Do NotMeasure - 0 145 9. "Local distance" switch in "local" position.

290290f

Use highV16 6W4 NC NC 470 - 225 -6.3ACf voltage insulated probe only.

f Top value is D.C. voltage to ground. Bottom valueV17 1B3 13.5KV 13.5KV 13.5KV' - 13.5KV' - 13.5KV 13.5KV connect A.C. meter across socket connections 7

8.

V18 5U4 NC310**

NC 305AC 290 305AC 290 310and

5.0AC Top value is D.C. voltage to ground. Bottom valueconnect A.C. meter across socket 2

V19 CRT 0 5Pin 10 Pin 11 Pin 12

connectionsand 8.

365 33 6.3AC --,,

73


ANTENNATINMINAL

!TRIP

R330I

-

LI

10

ANTENNAOR ES AAAAAA ANTENNA

VI30011. INPUT R F AMPIMPEDANCE

DLT

R22206

Series 123, 124, 124-2

THIS SCHEMATIC DIAGRAM FOR USE WITH ALL CHASSIS STAMPED IN REAR

SOUND I.F AMPLIFIERV8 6AU6

UPPER RIGHT HAND CORNER SERIES 123, 124, 124-2

TO CONNECT EKTERNAL ANTENNA

LOOSEN ANTENNA TERMINALS2-11(310v1 THE BUILT-IN ANTENNA LEADS.3 -CONNECT 3000 LEAD-IN FROM (ETERNAL

ANTENNA TO THE ANTENNA TERMINALSTI106.ND TIPITEN TN( SCRENS.

680 7A/6BZ 76 r--1

:10Thca 1, !i5-3 1 I L 3

I

I

5 r .516'14 47

C2 000

RS154

CIS3-9 47K

L51

TEST e>20622 247 MC cis

L 0 TI I2C

V2MIXER -05G.

6J6

I R4I 1011

4

I C:11

R710K

-3

CIO

C2I

I.__ rws __C12TIMING

C14. T 0156

WHITE

R69

C231 -.I5000 I 2211

C29I4 Me

450VA

IJTv 11211D60 CYCLEA C ONLY

f3 AmP

LINE FUSE

C76.6

RIO15k

C 230.5000

8113

1200%

Mh22/

INTERLOCK ON "BACK OF CHASSIS

ON -OFF SNITCHHANGED TOVOLUMECONTROL

RCA

R740016

10%

KEY TO SCHEMATIC

"K"=KILOHMS "M"=MEGOHMSUnless otherwise noted:All capacitors are in MMF, ±20%, and rated at400W V.All resistors are in ohms, ±-20%, and rated at1/2 w.All waveshapes shown are with an input signalsufficient to develop a 3 volt peak to peak com-posite video signal at the 'video detector. Contrastset at maximum, all other controls set for normaloperation.

L.V. RE CT.VI8 5U4

WI

RY

:AW.117

2750

L17ROA

IO

2

L

:3vT 3AMPS626.

MYINAT !EA/APS v,

NNE .T211

6. 3v AT 6.5 sows

CAPI02IF

400V.616

12.

6116

C92 (39010%

C91 810000 47n

210%C 93AN000

rlo

Ai:Alio_R. T_ ASS _

Toil

RIO,100

C,90.38

40

PRINOT

IK

4 516C.

RATICV9AI/2- 6

15001C 95

i ST VIDEO I.FV3 6CB6

LOCAL-015TANCE'SwiTON

5 3- -

44//56126

210.4

225V

240 MCTI vEL

5

61,761

010%

330

- C220

anaR19

2Ka%

2 NO VIDEOV4 6CB6

2120

102.

CII500

C22.1 C21A5000 5000

CI

125 my200 V

RP,100

R45000612M

R474750 A C35

ICIVI 1350 5000

FOCUS CONTROL-.0W

R46 R662254W0 A 470210%4W

35061 L le

FOCUS COL

MINIF D M4C0640

CONNECTION OFMULTI -SECTIONED

(LEGION:X.671C CAPACITORS

PART NO SECTION SYMBOL f CAP a W Vea C-62 40%, -50v

C-5455-3 M C-64 ROME -4500

C-72 4 mr -300- C-104 4 MF - 450V

C- 6 3 405E -450V

C-5435-3 C- 31 40 ME - 450v

A C 29 1 Vf - 450v- C -I06 MF - 4500

C-50 100MF- 50VC-5.429 2

A C-102 251F 50V

CSI

RAO5t10%

3

00 T R49

530K R5I TO22 C43

.210%3.6R ml

5%

SYNC. SEPARATOR

VIIA 1/2- 6SN7

45056G

_10%"'TCO2210

6

SYNC.AMPLVile 1/2-6SN7

COO2.2x

710%

R533.50

CA1

VERTICAL

34220

Coe2000

022 Air

HORIZ.OSCILLATORVI4 6SN7

12 873.30.0% ICU

V

HON HOLD

6.20.IO

R0576±10%1W

%A.A.

16011 FRED AD. pee476,0%

I if .

C

HORIR STABIL I

( C159330±10%ay 071

R83 6000 12000 6)%

1000!5%

Res706

150147

C 73560' 1

225 v

C7440-370'NORtong

C75

5%

74

IMOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION

C974-50 0.

AUDIO AMPLIFIERV98

2-67 8

C99C98 5000

5000

KF

I 2100

DINTC

VOLUMECONTROL

410910 OA

ROO470

AUDIO OUTPUTVIO 6K6

TRIODECOL/PLATE

CIO'01 1AF

RIII470x

RI It540

J 010%)4/

Cff/30047NE

3 6000

. ClotT25 hi

50 V

A.

fit

Tll

C104:50 V.

-2, 3.2Av.0

R 113470

I

Majestic Series 123, 124, 124-2

3 RD VIDEO IFV5 6AU6 23.2

411

0258

422 C2612 K 5000

C254 ',235000 !CS

424, no%

223O 0

r4

VIDEO OFT.V6 A I - 6AL5

- Ct?

L /0

TEL DOT600

Sn

RPO126 10%

C2I]3 T

A. G .0v6e

1/2 -641_5 zrTh

VIDEO AMP.V 7

y2-12BH 7

itilLUE 007- 4, TEST 80NT229 76010%

R44IOOK

ION

1121100

CONTRASTCONTROL

2301.59

404

233 336 210%

VIDEO AMPV7 B L

V2-12BH7 TEL DOT

,341 C ld,CL

C30 DOT

.22 1238 2493

1/400 % 2 711

20%

234 5 3 23*231 396 63 39 9- 2.761,0%

2r.l'10%

24010

C311.22W

R72706

R 4241710.10t

R411001,

141130.111455CONTROL

C3tIs

CM

C32.111F

ff 432208

ION

2250

VERT. OSCILLATORVI 2 6C4

/ c47.± TItE2. L!'_._,../.EIE°1E 4100110%

(vE7(l

L,

RT osc TRANS

Ks, 856211 26 a 26 1310n

R37 cArEft IL'0,47W

16521

1,70

S

11 I C48I1115-C:050 3'040'0T 110% 60ov1 W

2 KM

C

II

L__J L_ vERT NOLDCONTROL

5Y

75

R71INK010%

R61

2.514

vERT. SIZECONTROL

VERT.OUTPUTV13 6V6

C rt4 VI

_T 4500HORIZ. OUTPUTVI5 6 AV5

29i100

003/0 2

8901

zz

N.V. RECT.

VI7 1B3

Cr60478$

4000

4925.68010%2

9 2933.1

R 70 3309NA".

C1064 NF4500

2944706 I

TEL

C33047 IIFF

PICTURE TUBE

V 19

010'

560655.

267 .560

RED

J

0645 VERT

DEFLCOILS

6

C 79

502060

019NOR SIZE

C 8039010%

20000R 93

4706 = ION

r5415%

260

25W200v

R96 150 IMF2

1/4 AIDOVERLOAD

FUSE

LIESNOR.0EFL.COILS

65 V

NOR. DAMPERV16 6W4

020NOR LIN

066ton

CJ/047 SF ION6000

CO..01518F 110%600V.

'BOOST'

C83602000V

DEFLECTION YOKE AND FOCUS COILPLUG AND SOCKET CONNECTIONS

o ca 892.R96 8,16

2750 f p,7,OF via

225V

COILLM

R39R47F2

SOCKET

To 019 aP1718 OF 19

C130

TO vERTOUT RER

TO VERTWT 4-F RER

8L0(

1

IVERTDEFL LIRA

75


Majestic Series 123, 124, 124-2

Alignment I nstructionsTV I -F ALIGNMENT

1. Tune receiver to quiet portion of TV High Band.2. Set contrast control fully counterclockwise.3. Apply 3 v. negative bias between the A.G.C. bus (at

C22A) and ground. (Use 2-11/2 v. cells.) 04. Connect TV I -F Signal Generator through a 1600 MMF

condenser to Test Point (A) of tuner unit; low side toground. (See schematic diagram.)

6. Connect negative lead of V.T.V.M. (or meter of 20,000ohms -per -volt, or better) to 4.7K diode load resistor TESTPOINT (B); positive lead to ground. (See schematicdiagram.)

6. Feed 23.2 MC [23.3]* ( ± .05 MC) from Signal Generator,and adjust T4 for maximum deflection on meter. MaintainSignal Generator output so low that meter reads no morethan 1.5 volts at peak.

7. Feed 21.8 MC [21.8]' ( ±.05 MC) from Signal Generator,and adjust T3 as above.

8. Feed 24.0 MC [23.9] ( ±.05 MC) from Signal Generator,and adjust T2 as above.

9. Feed 24.7 MC [24.5]* ( ±.05 MC) from Signal Generator,and adjust T1 as above.

10. Replace the meter with the vertical input of an Oscillo-scope through a 10K isolating resistor, low side to ground.

11. Remove Signal Generator. Feed a video I -F Sweep Gen-erator (20 to 28MC) through loosely coupled shield of 6J6converter tube, making sure shield is not grounded. (Referto Fig. 3.)

12. Loosely couple high side of a TV I -F Marker Generatorto the high Sweep Generator Lead; low side to ground.

13. Feed I -F Sweep, and observe response on 'scope. (SeeFig. 5.) Use marker frequencies 20.25, 21.75 and 24.75 MC.

14. If response does not approximate that shown in Fig. 5,repeat steps 4 to 9, making sure that frequencies are pre-cise, and that the Signal Generator ouput voltage is keptlow. Continue with steps 10 to 13. A slight touch-up ofindividual slugs may be required to approximate the rec-ommended curve of Fig. 5.

*NOTE: If 3v fixed bias is unavailable and zero fixed bias isused, set signal generator at [ ] bracketed frequencies values.

IMPORTANT: Keep the sweep generator and marker gen-erator outputs at minimum to avoid curve distortion. Markerpips should be kept barely visible.

SWEEPSENEAATOR

ICORr[,

V2616

V7A'/2-125H7

TOWA NOWT0. *GOON A.

GENERATCNI

NE NINA. E. Es.. *AEA NE

Out INET-

RIv%.1%

OSCNE.OSCo.

eve.,ANNIT

too* a

TOV. SASEGoo S.

GENERATOR

FIG. 3. IF ALIGNMENT BLOCK DIAGRAM

30011TWIN LEAD

VI

G IS

G

0

TOP VIEW

TEST POINT

B Qt

FRONT VIEW

TV SOUND ALIGNMENT

1. Connect a 4.5 MC Signal Generator ( ± .01 MC) through a1500 MMF condenser to the grid, Pin 7 of V7, 12BH7; lowside to ground. See schematic diagram.

2. Obtain two resistors of approximately 100,000 ohms each,whose resistances have been matched accurately with anohmmeter. Connect them in series across the 18K resistor(R107) at the 6T8 tube socket (V9A).

3. Connect negative lead of V.T.V.M. to junction of matchedresistors of step 2; positive lead to ground.

4. Feed 4.5 MC ( ± .01 MC) from signal generator, and adjustL22, sound take -off coil, for maximum deflection onV.T.V.M.

5. Adjust the bottom slug of T10 for maximum deflection onV.T.V.M.

6. Connect positive lead of V.T.V.M. to junction of C98, andR106 TEST POINT (C), leaving negative lead of V.T.V.M.connected as in step 3. See schematic diagram.

7. Adjust top slug of T10 for zero output on V.T.V.M. be-tween two opposite polarity peaks.

MARKERS MAY UON PEAKS BUYNO LOWER THAN30% BELOWMAX.

TV RFRESPONSE

FIG. 5. RECOMMENDED RESPONSE CURVES.

76


PRODUCTION CHANGESThere are two different ratio detector transformers (T-7) used in these receivers, PartNumbers 9A2269 and 9A2295. The T-7 circuit shown in this schematic diagram coversthe 9A2269 ratio detector. Receivers using the 9A2295 ratio detector can be identifiedby the following changes:

C-18 becomes 47X570 330 mmf molded mica condenserR-15 becomes B84333 33K ohms 0.5 W carbon resistorR-18R.19/ become B83103 10K ohm 0.5 W carbon resistors

In addition, the 9A2295 ratio detector has terminals with numerical identification(1, 2, 3 etc.) whereas the 9A2269 ratio detector has terminals with alphabetical identi-fication (A, B, C etc.)

TELEVISION

RECEIVERS

MODELS

WG-3071E&F

WG-3073E&F

WG-3075D&E

WG-3077D&E

WG-3079D&E

Circuit diagram printed below and on page 78. This division is made to simplifyprinting and is not an actual physical separation.

re1YCif;11I-f ;357-Y,f'; .14/

S 17

I OR CII4NMEL DESIRED.

6827,R -F AMP ,:20

1 5

3

/ 1C.207I T 0 ii, C-204 2 1 IIr

0 3.31 si

A.O.C. HEATER 8.3 V

V-/6J 6 ; B 6

MIXER OSC. I /ST6CPIX I -F47

o1.1.17. I L58 L58 -01

5 -4..

R -F ^ ' 0.214

..-0 r .111 JC 213 20

<7(;05: .71220 n

C-2011 .io,II 20I1 '

TIt

H..,..

MO4: (-21.., C211 ,_,

71346,44CTi,,,,,-

c 2171

II.4.9

iC-212,000

08204

30 R -F/ 475014

VHF TUNER

ALL RESISTANCE VALUES IN OHMS.

ALL CAPACITANCE VALUES LESSTHAN 1.0 IN MF AND ABOVEIN MMF UNLESS OTHERWISE NOTED.

COIL RESISTANCE VALUES LESSTHAN I 0 OHM ARE NOT SHOWN.

MitERLOCF

T-10./ POWER TRANS.

I 6.1 v1oi Cc, ,

L -57g

R I

8 28

L-60°8 612

10

c 2131 F--i

RED'

84 IMIXER,o/S0V

T -I/ST PIX/-F CO/L

R-30IA

co

88.3VAC 8o -

6CB6-I

. ,

V-26CB6

2ND PIX I -F

T-2 V-3 T-32 NO Pile 6CB6 3RD PIX/-F COIL I -F COIL

R6

R-7

22KR-8..0 I

-

R-3OI R-32 R-108IS 150 2 5

,,,,A55,0, 0CONTROL

L

R-63 R 64 , V-7478 10K 68 E 6

SYNC. SEPARATOR5

ar,31,_ L-18

0300V 48.50V 4ISO

R-5826

FILTER. R-39IkCHOKE '40 7.5 MEG.

vc, R 109 16a -1,AI- R 59 SYNC. S TAB& / I'

6C 64

10KI' 6.. 100K

V-205U4 -G

L.V. RECT.

_..§2V

coPT 1 r-

ta.oa)

R-9ry

I 5 K

O

L -2 6CB6Ina .444D0-0 oL-3 GALS

TO 64,5 0,006S

R 68A R-686 R -68C22 8.2 8.2 '

Im

TV-58 -

12 AT 7PHASE SPLITTER

R-672.2 K

Iuc

2 -IO

R 33?.7 MEG. z

3 :61

0

M

5-- 0O

OJ

6 0

8

7.1a)

9 (.,34

R-24100 A

cn

R4.7 MEG.'-:

10 a)

77


t--

(1)40Cd

a.

O

MONTGOMERY WARD & CO.(Continued)

Models 35WG-3071E & F, and 35WG-3073E & F areidentical to models 35WG-3071D & 3073D except for thefollowing changes.

1. The 21" glass rectangular picture tube (21FP4A)has been replaced with a 21" metal rectangularpicture tube (21MP4).

2. Change in values of a few resistors were made inaddition to the picture tube change.

1

V-4 A6AL5

C.)PI% DE T.

frC.)

0

0Gt.

40 3 R344701(

r -I

O

"Cl

a,En

a)

O

O

V-106AU6

1ST AUDIO I -F5

R -IIL-13100 =

SOUNDTAKE -OFFCO/L R -I2

IK

RIOI 22 K I

I L-5160 0412. /1

R-361001( R-37

4.76

R 3847 K

6AU62ND SOUND I -F

5

V -5AI2AT7VIDEOAMP.

.I,U G R-91

I1(250

L. R69 R70 '''....-- 15-i 3.36 2.216 -ir,,,,,,;,O is

7

O 8V-/s6AL5PHASE

"CiDE T.

a) 9

G1

cd

10R-75

4) 470 K

$.4

R 76_27K

V -If6AL5

RATIO DEr

T-7SOUND RATIODE rTRANS.

15KR-42

R -4I R-43

331( I MEG '2'

*150V

IV-9

6AU6A.G.C.

VERT. 1

OSC. I a

R 82I.

MEG.

R-96 R-972.2K 1501(

.650

1,--Rr.11:49

Models WG-3075D & E, WG-3077D & E and WG-3079D& E are identical to models 25WG-3075C, 25WG-3077Cand 25WG-3079C except for the following changes:

1. Beginning with the issue "D" receivers, V-18 6W4-GT damper tube was replaced with a 6AX4-GTdamper tube.

2. Slight changes in cabinet construction and designwere also made on the issue "D" and issue "E"models. This change affects pix crystals, masks, etc.

V -I3

6AV6/ sr AUDIO AMP.

TONECONTROL

R-721.5 MEG.

R-71 R-231 MEG. 10 MEG.

VOLUMECONTROL

L -II/DO MU

844 ---0/1M100 R.84

100 K

0.300 V

R-25 500 KBRIGHTNESS

6AQ5AUDIO OUTPUT

3

V -4B6AL5

D.C. RESTORER

R-50I MEG.

R-552.2 K

V -B VERT. OSC.8 L -I26SN 7 VERT. OUTPUT p,,VGRrirON COIL .5

G rA

11-85820

R 51 vc- or R-87MEG.IS H000 2.2 MEG

e '2554fft (71

6.1 k.3",

R-99 R-I0015.615 47016

150 KH09/2

OR/ YE

6-It iR-93r

1 _ Iso o oR-516007uI

' '-' ...; R: 09

MEG:

2 . 11 E R -59680

i-o-NAA--Q

R90,8 MEG lil--.3 "" T-9

R-95 -.-g,-: HORIZ. OUTPUT s6.81(" ''' N.V. TRANS.

,-- ,.i-- -,GONI,OL

HeIGA+r1,3 --4. 1 V-/9R -1C3 47K

Is 11133-GT

1

H.M8R10( 4CT

5 1

V-2/21MP4

11-0 3000

`,-";:R -1000I

..J2z1(

1 0

G.

V -I6 94R V-17 300,6SN7-GTA r--4 50 K 6BQ6-GTHORIZ. OSC. # IIORIZ. HOLD NOR/Z. OUTPUT

T-5VERTOUTPUTTRANS.

AlNa

S

I v-/8?, 6A X4-GT

L, I DAMPER

..°ae 0.53+,

r G

101T-8

AUDIO OUTPUTTRANS.

R-2916

1250 2.

R -i051 MEG.

73.

L-15WIDTH

CON TROL

L -I66E5 moayr.comrRoc -0

X I L-17INOR/Z.DTIELLEC-

.300v

78


Motorola TRECEIVER MODEL BREAKDOWN CHART

Model DescriptionTV

Chassis

2103

Y21C3

21C3B

Y21C3B

21K20Y21K20

21K2OBY21K2OB

21K21Y21K21

21K21BY21K21B

21K22

Y21K22

21K23

Y21K23

Table, red-brn mahogany: masonite; TS -528with detachable console -height legs

Table, red-brn mahogany: masonite; TS -528Ywith detachable console -height legs

Table, limed oak; masonite; with de- TS -528tachable console -height legs

Table, limed oak: masonite; with de- TS -528Ytachable console -height legs

Console, red-brn mahogany: masonite TS -525Console, red-brn mahogany: masonite WTS-525YConsole, limed oak: masonite WTS-525Console, limed oak: masonite WTS -525YConsole, red-brn mahogany: masonite TS -528Console, red-brn mahogany: masonite TS -528YConsole, limed oak: masonite TS -5Z8Console, limed oak: masonite TS -528YConsole, white birch: wood; with TS -528wrought iron stand

Console, white birch: wood; with TS -528Ywrought iron stand

Console, red-brn mahogany: masonite; TS -528with turntable mounted on wooden legs

Console, red-brn mahogany: masonite; TS -528Ywith turntable mounted on wooden legs

CHASSIS

CHASSIS

TS -525TS -528TS -603SERIES

Model DescriptionTV

Chassis

21K23B

Y21K23E

21K24

Y21K24

21T18Y21T18

21T 18BY21T 18B

21T19Y21T19

21T 19BY21T19B

24K4Y24K4

24K4BY24K4B

24K5Y24K5

24K5BY24K5B

BREAKDOWN CHART

ChassisPictureTube

VHFTuner

UHFTuner

UHF Con -version Kit

RTS-525RTS -525YWTS -525WTS-525YTS -528

21YP4A21YP4A21YP4A21YP4A21ALP4A

TT -70YTT -70YTT -70TT -70YTT -70

WTT -37

WTT-37

WTK-35

WTK-35

WTK-35

Console, limed oak: masonite; withturntable mounted on wooden legs

Console, limed oak: masonite; withturntable mounted on wooden legs

Console, white birch: wood; withlift door

Console, white birch: wood; withlift door

Table, red-brn mahogany: masoniteTable, red-brn mahogany: masoniteTable, limed oak: masoniteTable, limed oak: masoniteTable, red-brn mahogany: masoniteTable, red-brn mahogany: masoniteTable, limed oak: masoniteTable, limed oak: masoniteConsole, red-brn mahogany: masoniteConsole, red-brn mahogany: masoniteConsole, limed oak: masoniteConsole, limed oak: masoniteConsole, red-brn mahogany: masoniteConsole, red-brn mahogany: masoniteConsole, limed oak: masoniteConsole, limed oak: masonite

TS -528

TS -528Y

TS -528

TS -528Y

RTS-525RTS-525YRTS-525RTS-525YTS -528TS -528YTS -528TS -528YTS -603TS -603YTS -603TS -603YTS -603TS -603YTS -603TS -603Y

ChassisPicture

TubeVHF

TunerUHF

TunerUHF Con -

version Kit

TS -528YTS -603TS -603Y

21ALP4A24DP4A24DP4A

TT -70YTT -70TT -70Y

WTT -37

WTT-37WTK-35

NOTE: For UHF Tuner Service Information refer toseparate UHF tuner service manual.

CHASSIS DESCRIPTION

RTS-525 18 circuit tubes, a 21YP4A rectangular 21" alu-minized picture tube (70° deflection angle) plus agermanium diode detector and selenium recti-fiers. A single chassis contains the picture,sound, and scanning circuits plus the filament.and "B" supply.

A switch type VHF tuner incorporating a cascodetype amplifier is used. Chassis with a "Y" suf-fix have, in addition, a built-in continuous tuningUHF tuner.

The IF strip consists of three stagger -tuned,transformer coupled,stages while the sound sys-tem uses a ratio detector and limiter driven byone stage of IF amplification.

The video circuit uses direct coupling and pro-vides full DC restoration. A keyed, delayed AGCcircuit is used.

The heater voltage, for all tubes except the highvoltage rectifier, is supplied by a filament trans-former. The selenium rectifiers, operating asfull -wave doublers, supply the low voltage "B"supplies.

WTS-525 Same as RTS-525 except picture tube is mountedwith a 5 degree tilt.

TS -528 Same as RTS-525 except for 21ALP4A, a 21" alu-minized rectangular (90° deflection angle)picturetube. The vertical and horizontal output anddamping diode tubes are also different types. Anexternal horizontal centering control has beenadded to rear panel.

TS -603 Same as TS -528 except for 24DP4A, a 24" alumi-nized rectanguliar (90° deflection angle) picturetube.

(Continued on the next five pages)

79


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81


Alignment Information for Motorola TS -525, TS -528, and TS -603 Series

15% VALLEYALLOWED

50-65%

42.25

41.25

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FIGURE 8. TUBE LOCATIONS & IF ALIGNMENT DETAIL

IF AND MIXER ALIGNMENT

1. Remove horizontal output tube (V-16) to eliminate RF in-terference. Connect a 2500 ohm 10 watt resistor from chas-sis ground to B++ (250V bus) to normalize voltages.

2. Remove antenna and make following connections: (SeeFigure 8).

a. Connect a 6 volt battery between pin 1 (IF AGC bus)of service test receptacle and ground. Positive side of bat-tery goes to ground.

b. Disable tuner oscillator by grounding pin 9 of V-2(6U8) and turn channel selector to channel 13.

c. Connect sweep generator to IF test receptacle andoscilloscope to detector load resistor (pin 3 of service testreceptacle).

3. Center sweep frequency at 44 Mc with a sweep width of10 Mc and adjust generator output below point of receiver

limiting (approximately 3 volts peak -to -peas at detectorload).

111

VI8183GTPV REST

VI6 HOW HOR OUT (TS -525)

09 4 826-S1)113dMVO loonys /IA

Adjust At Marker Freq. For

T-5 top 41.25 Mc Minimum, See Figure 8T-6 top 47.25 Mc Minimum, See Figure 8T -5 bot 42.25 Mc Marker at proper point,

See Figure 8T-6 bot 45. 75 Mc Marker at proper point,

See Figure 8T-7 bot ton of curve Flat too. See Figure 8

As some adjustments interact,tain proper curve.5. Move generator to mixeracross R-1054. 7K ohms). See

L-19 & 42.25 -L-25 45. 75 Mc

repeat as necessary to ob-

test receptacle and shortFigure 9 for R-10 location.

Proper curve, See Figure 8.If desired overall responsecannot be, obtained, checkdressing of bypass capaci-tors, especially the screenbypassing of the 1st & 2ndIF tubes. These leadlengths are critical andshould be kept short anddressed to obtain properresponse.

82


MOTOROLA TS -525, TS -528, TS -603,

CHECKS

Bandwidth may be determined by noting the frequenciesat which the markers fall at the 50% points. Mixer and IFbandwidth over 3.7 Mc may cause sound bars or burble inthe picture; if less than 3 Mc, a loss of resolution or finedetail in the picture may be noticed.

6. Decrease generator signal until there is a marked de-crease in the oscilloscope waveform. Unwanted regenera-tionwill be indicated by sharp peaks on the overall responsecurve. If regeneration is present, check IF cathode re-sistors, screen bypass capacitors, and lead dress. Im-proper alignment may also cause regeneration.

AUDIO ALIGNMENT

This alignment may be made by injecting an accurate4.5 Mc signal in at the video amplifier grid. However, thestation alignment method which follows is much more ac-curate and should be used whenever possible.

1. With receiver in operating condition, tune in station.

2. Connec-. VTVM from positive terminal of electrolyticcapacitor C. -50B to ground.

3. Maintain 5 volts, or less, at VTVM by adjustment offine tuning and contrast control (or by removal of antenna,if necessary) while peaking T-8 primary (top) and L-38 &L-39 for maximum output. (See Figure 8.)

4. Tune for normal picture and carefully note voltage de-veloped at the positive terminal of C -50B.

5. Move meter to junction of R-54 & R-56 (dummy pin onV-9 socket, marked "X" in Figure 8).

6. Adjust T-8 secondary (bottom) to give a reading on theVTVM of exactly one-half of reading in step 4.

4.5 MC TRAP ADJUSTMENT

Tune receiver to a local station and adjust 4.5 Mc trapL-34 for minimum beat interference in the picture by lo-cating the two points of adjustment at which the beat is justnoticeable. Rotate the core toward the center of these twopoints. Use the minimum amount of inductance (core out ofcoil) that will result in no apparent beat interference.

HORIZONTAL HOLD ADJUSTMENT

The HORIZONTAL HOLD control should have %syncrange of approximately 20°. If the control is too critical,adjust as follows:

1. Shunt the HORIZONTAL OSCILLATOR coil 1.-40 toground with a .25 mf 400V capacitor. This may be donewith the chassis in the cabinet by placing the capacitoracross the two -pin HORIZONTAL OSCILLATOR TEST RE-CEPTACLE. Increase brightness.

2. With the HORIZONTAL SIZE control, reduce the picturesize so that the right edge of the raster can be seen asviewed frcm the front of the set. Adjust the HORIZONTALHOLD control for about 1/16" of sync pulse. (The syncpulse appears as a darker gray bar at the right edge of theblanking pulse. The blanking pulse is the gray bar at theright edge of the raster.

3. Remove the .25 mf capacitor from across the HORI-ZONTAL OSCILLATOR coil.

4. Adjust the HORIZONTAL OSCILLATOR coil until thesame amount of sync pulse can be seen as was noted instep 2.

Alignment and Service Data, ContinuedIf the deflection yoke shifts, the picture will be tilted.

To correct, loosen the thumbscrew on top of the deflectionyoke and rotate yoke until the picture is straight. Beforetightening the thumbscrew, make certain that the deflectionyoke is as far forward as possible.

ION TRAP ADJUSTMENT

1. Turn on the receiver and set brightness control at mid-range.

2. Rotate the ion trap from left to right, and position backand forth until the brightest raster is obtained.

3. Adjust for proper screen coverage regarding size, cen-tering, tilt and shadow.

4. Readjust ion trap for maximum brightness with contrastcontrol set for maximum usable contrast and brightnesscontrol set for proper black background in picture.

NOTE: The ion trap should be of the proper magneticstrength, so that the ion trap magnet does not touch the baseof the picture tube, or be positioned forward of the slash inthe gun structure at proper setting. If either of these con-ditions exist, full brightness may not be obtained, and thelife of the picture tube may be shortened if the ion trap isnot replaced with one of correct strength.

PRODUCTION CHANGESThe first production chassis number carries the suffix

"A-00" (i.e., TS -525A-00). With the first minor electricalrevision, the suffix becomes "A-01" and with each subse-quent minor change "A-02", "A-03", etc. The first majorrevision changes the suffix to "B-00" and, as before, eachfollowing minor change is labeled "B-01", etc.

Mechanical differences between chassis are indicated byaddition of a prefix to the basic chassis (i.e., RTS-525A-00).These prefixes maybe assigned In random sequence butwillbe confined to the end of the alphabet to avoid confusion withthe A, B, C, etc. , electrical change suffixes.

A"Y" suffix added to basic chassis (i.e., TS-525YA-00,etc.) indicates that the chassis contains a factory -installedUHF tuner.

ChassisCoding Changes

(TS -5Z5 Series Only)A-01 To improve the IF response C-38 (470 mmf) changed

to .001 mf; C-40 (560 mmf)moved to a direct chas-sis ground.

A-02

A-03

To aid the magnetic centering device in horizontalcentering and reduce neck shadows, a non-adjustablehorizontal centering circuit is added as follows:

1. C-106 (. 1 mf) replaced with linearity coil L-44to provide a DC path through the horizontal el eflec-tion yoke.2. Connection between lugs 4 and 5 of the horizon-tal output transformer (T-13) removed and an 18ohm resistor inserted between lugs 4 and 5 to forcecurrent through yoke.3. Leads of L-41 (RF choke) and R-83 (150K re-sistor) connect to lug 4 of the output transformer;the lead of L-44 connects to lug 5.

R-66 (4.7M grid to ground resistor of 1st sync sep-arator) changed to 1.5M and ground end re -connectedto cathode (pin 3) of V-13 to improve sync range athigh contrast levels.

83


TROUBLE -FINDING CHART for Motorola TS -525, TS -528, and TS -603.

SYMPTOM CONTROLS CHECK OR ADJUST TUBES MISCELLANEOUS CHECKS

SET DEAD (tubesnot lighting)

Off -On volume Is set plugged in? Isback cover on? Is ACline voltage available atoutlet? (Check with lamp)

Filament fuse F-1

(tubes are lit) Power fuse, R-64. Isspeaker plugged in? Re-place any tubes that donot light.

V -11

NORMAL RASTER Channel selector (on Antenna connections. Is V -1, 2, 3, 4, 5, B+ voltage. Video detector,NO PICTURENO SOUND

station?) station on air? 11 & 12 CR-1. AGC voltage. RF,IF or mixer stages.

WEAK PICTURE(insufficient con-

Contrast. Fine tuning.Channel selector on

Antenna connections V-1,2,3,4,5,6 & 12

AGC voltage. Contrastcontrol. RF, IF, mixer

trast) correct channel? & AGC stages

LOW BRIGHTNESS Brightness. Ion trap magnet V-15, 16, 17, 18, High voltage at picture tubeOR NO RASTER 19 & 11 anode. Drive voltage, pin

5 V -16. Bootstrap voltage.D+, B++ and CRT voltages.Solder connections, base ofCRT. Voltages & wave-forms in V-15 & V-16 cir-cuits. Horizontal outputtransformer & deflectionyoke.

POOR VERTICAL Vertical size. Vert lin. V - 14 Bootstrap voltage. Volt -LINEARITY AND/OR Reduce brightness & ages in V-14 circuit.SIZE.HORIZ. WHITE return to normal when Electrolytics, C-99 &LINE. (no vert.sweep)

trouble is cleared. C -74C. Vertical outputtransformer & deflectionyoke.

VERTICAL INSTA- Vertical hold V-13, 14 AGC voltage. Voltages inBILITY, PICTURE V-13 & V -14A circuit.ROLLS Interference. Sync clip-

ping at video amplifier.Refer to tests under WEAKPICTURE. Abnormalpower supply ripple. In-sufficient bootstrap filter-ing. Video detector.

BUZZ IN SOUND Fine tuning Excessive signal -V-7, 8,5. 10 & Ratio det. alignment. Synccontrast 11 clipping in video section.

Improper AGC action.Power supply filter & sweepcircuit bypass capacitors.Heater -cathode shorts insound tubes.

EXCESSIVE CON- Contrast V-1, Z. 3,4. 5, AGC voltage and AGC cir -TRAST.NEGATIVEPICTURE

6 & 12 cult. Video det. Videodet. load resistor. Leak-age between prim. & sec.in video IF coils. Properpulse from horiz. outputto AGC tube. Pulse coupl-ing capacitor to AGC tubeC-107

WIDE HORIZ. BAR V-1.2,3,4, 5, Heater -cathode short inOR GRADUATION INSHADING VERTI-

& 6 any video circuit. Excessive power supply ripple

CALLY (Set may havepoor Vert. sync)

(may have hum in audio).Selenium rectifiers.Heater -cathode.short inV -10A (loud hum in audio).Picture tabe.

84


MotorolaTV CHASSIS - Chassis WTS-518 contains 16 circuit tubes

plus a 21YP4 21" glass, rectangular, spher-ical face, electrostatically focused picturetube. The picture, sound, and scanning cir-cuits, together with a selenium rectifier half -wave doubler "B" supply, are contained on asingle chassis. A series heater circuit isused. The 300 ohm input impedance ismatched to the 75 ohm TT -69 tuner imped-ance by use of a balun line. Field installationof UHF convertor in this chassis is not rec-ommended.

The suffix "Y" indicates that the TV chassishas a built-in VTT-50MA UHF tuner and usesa WTT-24AY VHF tuner.

TS -418 - Same as WTS-5I8 except uses a I7HP4B alumi-nized picture tube. The picture tube mountingparts are changed to accommodate smaller tube.

VTS-418 - Same as TS -418 except uses a 17HP4 non -alumi-nized picture tube.

VTS-518 - Same as WTS-518 except for 21YP4A aluminizedpicture tube.

ALIGNMENT

NOTES: IMPORTANT

NEVER GROUND THE RECEIVER CHASSIS DUR-ING TESTING OPERATIONS OR INSTALLATIONUNLESS AN ISOLATION TRANSFORMER IS USED.

At all times, keep the marker generator output lowenough to prevent the marker from distorting theresponse curve.

Some coils resonate at two settings of the core, thecorrect setting is at the outer end of the winding.

For complete receiver alignment, use the followingprocedure in sequence. Line voltage must be 117volts AC; if not, adjust with variac.

IF AND MIXER ALIGNMENT1. Remove horizontal output tube (V-15) to eliminate RFinterference. Complete filament circuit with a 25BQ6 tubeor other type with similar filament characteristics and baseconnections, with all pins clipped off except heaters.2. Remove antenna and make following connections: (SeeFigure 4).

a. Connect a 3 volt battery to pin 1 (AGC bus) of serv-ice test receptacle.

TCHASSIS

TS -418518

SERIES

RECEIVER MODEL BREAKDOWN CHART

Model Description TV Chassis

17T20Y 17T2017T2OBY 1 7T2OB17T2OEY 17T2OEI7TZOMY 17TZOM21T16Y21T1621T 16BY21T 16B21T16EY21T 16E21T17Y21T1721T17BY21T 17B211(19Y21K1921K19BYZ1K19B21T 15Y21T 15

Table, mahogany -metalTable, mahogany -metalTable, beige -metalTable, beige -metalTable, ebony -metalTable, ebony -metalTable, maroon -metalTable, maroon -metalTable, mahogany -metalTable, mahogany -metalTable, beige -metalTable, beige -metalTable, ebony -metalTable, ebony -metalTable, mahogany-masoniteTable, mahogany-masoniteTable, limed oak-masoniteTable, limed oak-masoniteConsole, mahogany-masoniteConsole, mahogany-masoniteConsole, limed oak-masoniteConsole, limed oak-masoniteTable, maroonTable, maroon

TS -418TS -418YVTS-418VTS-418YVTS -418VTS-418YVTS-418VTS-418YWTS-518WTS-518YWTS -518WTS-518YWTS-518WTS-518YVTS -518VTS-518YVTS -518VTS-518YWTS-518WTS-518YWTS-518WTS-518YWTS-518WTS-518Y

b. Disable tuner oscillator by grounding pin 9 of V-2(6U8).

c. Connect sweep generator to IF test receptacle, andoscilloscope to video detector load.

3. Center sweep generator frequency at 24.6 Mc with asweep width of 10 Mc and adjust generator output belowpoint of receiver limiting (approximately 3 volts peak -to -peak at video detector load).

Adjust At Marker Freq

L-12 21.9 Mc min output (See IF responsecurve -Figure 4)

T-4 26.6 Mc 26.6 Mc marker (See IF re-sponse curve - Figure 4)

T-6 at top of curve flat response (See IF re-sponse curve -Figure 4)

T-5 22.9 Mc 22.9 Mc marker (See IF re-sponse curve -Figure 4)

T-6 at top of curve flat response (See IF re-sponse -Figure 4)

As some adjustments interact, repeat as necessary to ob-tain proper curve. (Move generator to mixer test recep-tacle and short across R-11 (4700 ohms).

T -3A 2.4 & 22.9 Mc& B

See mixer response curve-Figure 4. As adjustmentsinteract, adjust simul-taneously.

NOTE: If desired response cannot be obtained, rechecktuning of 21.9 Mc trap (L-12). Accuracy of this adjustmentis important

(Alignment continued on the pageafter the double -page circuit.)

85


MOTOROLA TS -418 and TS -518B-00 Series

NOTES

VOL TIOC NIA$11101ENTS.I. HYDE NoTH A VT. IRON POINT NOICATE0 TO CRASS&t ONE VOLTAU II? VOLTS

S ANTENNA ORSCONNEOTEla 1St IN LOCAL POSITION)CALLIONL SELECTOR SWOT. ON CHANNEL WITCH DEVELOPSLESS THAN I VOLT MSC AT PIN mee S OF TEST ACCEPT.

5 CONTRAST CONTROL KARMA CLOCKWISE POSTON.

4 ALL OTHER CONTROLS NORNAL OPERATOR. TOSTION.

7 or VANES MTN SETTNOIS OF CONTROLS

CAUTION. Do NOT AMEN, VOLTAGE WRONGSON THE 4536T OR SCOPE REM:M.5 oft THE 25806GTPL ATE WIT 14 TRE.NRY EONINENT

F--

220

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VI6C96

RF MAP

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R3L2E

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WIVE FORMS

OliStevt El ON DUMONT NOM L /44 OSC L °SCOPE

2 CON CONTROL SET FOR SIGNAL OF 450 P TO P ATPLATE OF VIDEO RAW TARE

ALL STRIA CONTROLS IN WHORL OPERATING POSITION

TWIG, NV GIN TIE REMOVED TO A.ANTATE ooy SASSINTERFERENCE FROM SCOPE RHIN ORSERvoK ALL- sAKFORNS,EAGER, THOSE F RON PHASE OE T THROOGN NOME Cast,

I17STORS NOKATED N OARS, 0.1000 OHMS

CAPAGTORS RTINCATED N NICROINCROFARADS UNLESSOTHERWISE SPEC., *NEN MPG A T m NKR°IIIKROFRAOS T ARE CERAMIC DISC, TAMA.. ORMA TYPES, E 'KEPT FOR VALUES SHOWN NRT NCOCK, SUCH AS 47.000, N.C ARE THE 001010PAPER TYPE SRO NKR( PONCA T CO

COILS MOICT E0 M NKRONENRIES

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IGROUNCI)

'ii

(II CONNECTIONS

87

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONMOTOROLA TS -418 and TS -518 Series, Alignment Information Continued

Bandwidth may be determined by noting the frequenciesat which the markers fall at the 50% points. Mixer and IFbandwidth over 3.5 Mc may cause loss of picture quality,and less than 3.2 Mc, a loss of audio.

5. Remove AGC bias battery, BANDWIDTH SHOULD NOTCHANGE OVER .2 Mc.

6. Decrease generator signal until there is a marked de-crease in the oscilloscope waveform. Unwanted regenera-tionwill be indicated by sharp peaks on the overall responsecurve.

AUDIO ALIGNMENT

This alignment may be made by injecting an accurate4.5 Mc signal at the video amplifier grid; however, thestation alignment method is much more accurate and shouldbe used whenever possible. Station alignment method fol-lows:

1. With receiver in good operating condition, tune in sta-tion.

2. Connect VTVM from positive terminal of C-54, elec-trolytic capacitor to ground.

3. Maintain 5 volts, or less, at VTVM by adjustment offine tuning and contrast control (or by removal of antenna,if necessary) while peaking L-20 and T-7 primary (top) formaximum output.

4. Move VTVM connection to junction of C-2 (1000 mmf)and R-45 (33K). Set fine tuning for normal picture.

SWEEPGENERATOR 1000

MMF

5. Adjust T-7 secondary (bottom) for zero reading onVTVM.

6. Recheck as in steps 2 and 3 and, if necessary, readjustprimary of T-7.


Tune receiver to a local station and adjust 4.5 Mc trap(L-17) for minimum beat interference in picture by locatingthe two points of adjustment at which the beat is first no-ticeable, and rotating core to the center of these two points.Use the minimum amount of inductance (core out of coil) thatwill result in no apparent beat interference.

If a station signal is not present, use the followingmeth-od, which requires proper alignment of the audio system.

1. Tune the receiver to a low noise, unused channel.

2. Connect AM signal generator to picture tube cathodelead (yellow) thru a 5000 mmf capacitor. Connect groundlead to chassis.

3. Set generator to 4.5 Mc.

4. Move VTVM to positive terminal of C-54 capacitor, withground lead to chassis.

5. Adjust 4.5 Mc trap (L-17) for minimum VTVM reading.(Generator output should be adjusted for 5 volts at VTVM.)

ANTRECEPT

HORIZOSGL23g

vi

6C56

MIXER ALIGN A. MIXER-.Irk- TESTv2 -1 r:.),RECEPT

6U8 Ril **,

MIXER RESPONSE

T 3 1:3IF TEST L

REGERT

F ALIGNA C54 1,14:

5v9 -T.-DISCBAL

(TOP) PRI

(BOT) SEC

VIO6SN7GT0.1.5( OLT

0LI7

4.5 MCTRAP

TUBE LOCATIONS & IF ALIGNMENT DETAIL

88


OlympicR - S - U CHASSIS

MODELS

17TR1O

17TR19

17CR20

21KS22 21CS18

2ITS11

21CSI2

21TS17

21TU14

21CU1S

21CU16

These models are nineteen tube direct viewing television receivers differing only in type of cabinet, size ofspeaker and their use in conjunction with a radio receiver and automatic record changer in the combinationmodels. A 17" electrostatically focused rectangular tube (17HP4) is used in the 17" models and a 21" magnet-icallyi21 ZP4Bfocused and rectangular tube is used in the 21" models. Replacement, in all cases, must be of

12IZP4Athe identical size and type.

DEFLECTION YOKE ADJUSTMENTIf the lines of the raster ore not horizontal or squared

with the picture mask. Loosen the deflection yoke adjust-ment screw and rotate the deflection yoke until thiscondition is obtained, and retighten the yoke adjust-ment screw. If neck shadow is evident or the corners o;the raster are dark, the deflection yoke must be movedforward as far as possible and the wing screw re -tightened.

-.ADJUSTMENT WING NOTTOR DEMME:01 YOKE

CENTERING MAGIETS

ION TRAPMEAN EIEMEIII

FIG. 2 21R.ONLY

CENTERING MAGNET ADJUSTMENT

(1711-"R" ONLY)The 21" receivers are electromagnetically focused and

centering is accomplished by adjusting an arm whichextends vertically from the front of the focus coil. Thisarm may be rotated, for a limited distance, around theneck of the tube and may also be moved up and down.The physical setting of the focus coil itself in relationto the neck of the tube will also affect picture position.

IF ALIGNMENT PROCEDURE

ORDER OF ALIGNMENT

When complete receiver alignment is necessary, itshould be performed in the following sequence:

(I) Accompanying Sound Trap(2) Adjacent Sound Trap(3) Pix IF Coils(4) 4.5 MC Trap(5) 4.5 MC Sound IF and Ratio Detector

After removing chassis from cabinet re -connect powerand speaker plugs.

If a local station is not operating on Channel 9 setthe tuner to this channel, turn on power switch andproceed as follows: (If 9 is a local station, use Channel8 or 10.)

CENTERING ADJUSTMENT (21" - S -U - ONLY)The 21" receivers are magnetically focused and

centering is accomplished by adjusting an arm whichextends vertically from the front of the focus magnet.This arm may be rotated for a limited distance, aroundthe neck of the tube and may also be moved up anddown. The physical setting of the focus coil itself in

relation to the neck of the tube will also affect pictureposition. Before the adjustment arm is used, it shouldbe ascertained that (I) the focus magnet is at rightangles to the neck of the tube (by setting the two nutswhich tighten the tube support rods) and (2) that theneck of the tube is directly centered in the focus magnet(by loosening the two mounting screws on either sideof the focus coil and sliding up or down).

HORIZONTAL WIDTH & DRIVE ADJUSTMENTThe Horizontal Drive Trimmer should be screwed

tight (clockwise) and then backed off (counter -clock-wise) until Horizontal Drive bars appear. Then turnDrive Trimmer in again (clockwise) until drive bars, justdisappear. (Note: In some sets no horizontal drive barswill appear regardless of Drive Trimmer adjustment. In

these sets the trimmer should be set for proper width.

Important: The horizontal oscillator frequency must bechecked for proper range of horizontal con-trol after any adjustment of horizontal drive(C67). Any adjustment of C67 will usuallyrequire resetting of the horizontal frequencyadjustment coil (L-16).

(Continued on page 92)

ACCOMPANYING AND ADJACENT SOUND TRAPSInsert a 100,000 ohm 1/2 watt resistor in series with

the "Hot Lead" of the electronic voltmeter and connectto the junction of L12 and C25. Meter switch should beset to the lowest negative scale. Ground lead of metershould be connected to chassis.

Remove the shield of the RF Oscillator and Mixertube (V2) from ground clips leaving shield resting ontube and connect hot lead of the RF Signal Generatorto it. This will couple generator output to mixer plate.

Set the generator frequency accurately to 21.75 MC,and adjust (L9) sound trap (See Fig. 6 Tube and TrimmerLayout) for minimum reading on voltmeter.

Set the generator frequency accurately to 27.75 MCand adjust (L6) Adjacent Sound Trap for minimumreading on voltmeter.

89

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONADJUSTMENT OF HORIZONTAL OSCILLATOR

(I) Allow set to warm up to operating temperature.Select station operating normally.

(2) Short out horizontal Phasing Coil (L 17) TerminalsC and D.

(3) Set horizontal hold control at maximum clock -wiserotation.

(4) Adjust horizontal frequency screw (L 16) untilpicture falls into sync. Turning the horizontal fre-quency screw (L 16) clockwise lowers the frequency,(bars sloping downward to left). Turning the screwcounter -clockwise increases frequency (bars slop-ing downward to right).

Connect vertical input lead of oscilloscope with5 MMF isolating condenser in series to terminal"C" of horizontal oscillator transformer andground oscilloscope to chassis. Set frequency ofscope to approximately 5 KC.

(6) Remove short from terminals of the horizontalphasing coil (L 17) and adjust screw (L 17) untilwave shape as observed on scope is like thatshown in sketch. (See Fig. 3.)

Some further adjustment of horizontal frequencyscrew (L 16) may be necessary to keep picturein sync after adjusting L 17 for proper wave shape.

Remove scope from terminal "C" and retouchL 16, as per "9" below.

Turn horizontal hold control through entire range.Picture should fall out of sync at either end ofrotation. At full clockwise rotation blanking baror jitter should be evident. At full counter -clock-wise position picture should fall out to 41/2 to 5bars sloping downward to the left. (If picturestays in sync the tuner switch should be rotatedto interrupt signal momentarily)

(5)

(7)

(8)

(9)

ADJUST FOR EQUAL PEAKS

ouTHrt.rem Her NET 111

110 CPS 205

m1.- INN

NMI APS 75v

VI) - PIN 5

30 CII5 1E0 Y.

VI3 Pm 330 CPS NNW

vir - PlOt71173 CPS no

reoneenea. e e. Hue I.Fill/11 CPS 150r

77v15 - uS71110 CPS Ov

FIG.3RUN N91 WAS: (CONDENSERS) C42 WAS .C6/400VAND C61 VAS D01/600V 10%10IL FILLED).(RESISTORS) R12 WAS 10K11; R30 WAS 471(112R; R38 WAS 331(.114 R46 VMS 22K).1R53 WAS 121(11±10%; R54 VMS L5 ME611410%;R76 WAS 22ICII 2W. FUSE WAS 1/4 AMP.

II

STATIONINLECTIM

'I

°JET'

OLYMPIC CHASSISMODELS: 171-PR; 21"-.S° 8 21.41

NTEINGA NWT

Seen TRANS. LINE LEAD lir

)404

FINETooCONT..

ANTINNA MET

O

ouTune OF TOME! CONTAININTOONE OE !ETA OF

K 15) C SACMS SAO,a.

6BZ7 oft 61307AVI

AE AMPLIFIER

L301WINE 0011

12 CHANNEL R.F. TUNER USED ON

21":1.1.MODELS ONLY, OLYMPICPART NO.CL-2755-T!".",?

100.011mol LINE LEAD IN

6BC5 oft 6CB6R F AMPLIFIER

000'

6J 6

a ISV2

C303 N.POIN CMPOOTEN

MOf

FINETUNIS,

CONTROL

.000

; /OM 1I 4. 140 V.RED/WANT[

TRAe-

12 CHANNEL R.F. TUNER USED ON& 21"=S' MODELS ONLY

OLYMPIC PART NO. CL -3402 tjounljo Tv -pooh,

47k

FILAMENTS

VIDEO LEmum/

it +140V

In VI

+140V.

1.1. LE- AOC.WirITE

1-41'

FILAMENTS

-r "I;Z:".""

L'441. VIDEO I.F.

301IS UK

M-N/WHITE

RUN Ng 2 WAS: ADDED COB CONDENSER; L10COIL AND R29 RESISTOR. (CONDENSERS) C58WAS .1/400V.; C61 a CAB WAS mule.(RESISTORS) R72 WAS 82)(11 *5% 119 ;R79 WAS 47KIL 1W.; 154 450V. UNE IN HOW.

0N orF sorrosOM WAS +3130V. ON Mum VOLUNF0020LINE

:or : v. c LLLLL (Kr FITROI.

RUN N2 31.11S SHOWN) EXCEPT USE 1133/037 Ci:=11TM V16) REPLACES 1028 AND TP.2771-2 110011[T 010

&WOWSHORIZ. OUTPUT H.V. TRANS. ITS) REPLACES [moot vexTR-2771-1.

NOTES:

Au. OSSIO7014 E .0 a TOLIalmoM S5 WATT 1.1.5.OT01111.11. 0270100.O.

FAA INCA He cmmeae 0000441144 21tOl R501.11A.054 MINIMISE 1.11CINIM.

3 ALL VOLTAIMS IMANI0110 POINTS INCIMATN0 "MAIAMP COMMIS, 1111140 AN luICTRONIC VOLTINTOILALL VOLTNE 001105851, CAMINO 1TN ANmoor vOLTA4 OF Tr VOLTS. Cr45/11, A.C. MTNT1001111. SONO& /IMO WITS 001FTRAIIT COOTOOLO POrmet PO VOLTS RAN TO PIM AT KINESCOPE.

*A COMM CONOMMIMAIL DISC TWO.

5U4GV18

RECTIFIER

0+265V.zt:ti MODELS

/ONLY

AINACENT 1011110 MAP I

27.75 OS I

9."- X (4.3',)

14P0101111

ToANSFOINNIN

90


L5 6AU61,75 MC. VONA LF.

SRO P/0 I.F.

6AU61/5

2. SOUPED I

I V.

OLYMPIC RADIO & TELEVISIONChassis R, S, and U

L4 L3 TN' 6AL5DETECTOR

04RATIO,15491(991.1119 RAT 10 DETECTOR

7

ISOn St. IRMA.05* C65301Aili .0O2/400T

V

VIDEO DETECTOR

L7 6CB6 L8 c'''' '`'m L11 L12. 2 ma in. on23.5 MC.V9 2515 MC m.ou no sneoFIN IF..IN I FEM PI LP.

11 r', -T 1

12AU7(1/2) 12AX7('/2)12A VI1A

SYNC. CLIPPER ST NC RENARATOR

Il ROY 1000.

C ES

.05/0000

R 40 0422 RIO

A10 RIOIE

6SN7/GT L16 L177063 V14

FOOOTCA PHASE

AID%m NIzoNTALeCOSCILLATOR

n71r

c --1IA ILVEIN

CAR47141

IO%MRILVERI

:+o: R73,,?

c571-2' lir-- -"Ars ...IL .sC54 C60.0 4000 55 ,51.1,(111 10000

:10.4 V 4:07

antf

7

ro'4.'068 69

VR70 R2150 5

IRA% MOM 6 5%.

12AX7(11/2)V1113

NC AMPLIFIER

+450V

DRITEtONTRoL

6AV6vs

AUDIO AMPLIFIER

+ 265V.

1 TO L500

PRINTED CIRCINTNERTICAL iNTEGRATOR T2

NETSFORK VERT1CLORIN/MUM PC -100 BLOCKiN

OSCILLATORTINSFORNER

TALLow

C39 Raj006/600 4200.11.

.10%

N.. C40

.0047/1100V RIOS.101,1..20) R51

LS NEILAAP%

6BQ6/GTV15

ON1AL OUTpuT

:arm

CONTRASTCONTROL

N

IvCONTROLol

12AU 7(1/2)VI2B

VERT OSCILLATOR

VERT 4EIGNTCONTROL

6W6/GT

.010 OUTPUT

1130K.D..10%

+140V.

SOUND I F

.V4000052

17A'

+275V.

1X2B oa 183/GTV16

Hi. VOLTA. RECTIFIER

T5NoRIZON AL OUTPUT IR. VOLTAGE

TRANSFORM.11.4/4.'

MART *04. rIn17112 -10 EA,

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+275V.

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VERTICL OUTPUT

T1Roo ID

OuTPuTTRANVOINIMI

VERT LMEARITYCONTROL

SPERM,

RII

+275V.

TO +265V. (ON 21.:11 MODELS ONLY)

POINT ON TUNER.RECTANGULAR

17H P4A21ZP4A21Z P4B

VI 9KINESCOPE

R34220 Ha

L

. TEND ON MOOELS

TO .T OF THE FOLLOWING FOR OPROPER FOCUS

B+ 275 V.OR

B+ 550V.

B - CHASSISOPIIONTAL FAA. 0

BLANKING

T3VERTIIRANCAL VOWEL,. CO,

I II

T

mmt _-aeonA,04

O-TC46 R59o RFD/

550 v

+310V.

1 OR VOLTAIRE

/0 KINESCOPE

15KV.

+450 V

6W4/GTV17

DAMPER

C63

V4000

566!00 00My.

Y Y

+275V.

rootmon 1IONTAI DIVLECION COIL

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HORIZONTAL BLANKING

91


VT VM

0

I

VOLTMETER AND CRYSTAL DIODECONNECTIONS

FIG.5

PIX IF COIL ADJUSTMENT

Olympic Chassis R, S, and U (Continued)TO C.R. TUBE

\\\CATHODE LEAD(YELLOW

1.75 MC

23.0 MC.

26.25 MC.

2775 MC.(ADJ. SOUND TRAP)

50%

STANDARD RESPONSE CURVE FIG. 4Adjust the following slugs for maximum output at fre-

quencies and sequence indicated with meter and gen-erator connected as above: (See Sound Traps above).

L301 22.5 MCL5 25.75 MCL7 23.5 MCL8 25.25 MC

Note: After setting L5 DO NOT readjust to improve

wave shape.

If oscillation occurs during alignment, temporarily raisefrequency of L8 by turning screw counter -clockwise untilscrew projects approximately 3/4''. Oscillation is evi-denced by high reading on voltmeter (-5V to -20V)with signal generator OFF and no signal coming inthrough the antenna terminals. After properly adjust-ing L301, L5 and L7 reset L8 to proper frequency, if ithad been necessary to detune.

Connect hot lead of sweep generator through a 330uuf condenser to test.point on tuner and connect groundlead to chassis.

Connect vertical input terminal of oscilloscope tojunction of peaking coil L12 and C25 and connectground lead of scope to chassis.

Connect I .5 V flashlight battery with positive terminalto chassis and negative terminal to junction of R13 andC2I. This point is AGC bias voltage. Set tuner toChannel 9 unless local station is operating on this fre-quency, in which case an adjacent channel should beused.

Set Sweep Generator frequency to IF sweep on the20 to 30 MC range.

Adjust sweep generator output to produce a curveon the scope which is approximately 2/3 of the screendiameter.

Loosely couple output of RF signal generator byusing shield on V2 and set frequency of RF signal gen-erator to 26.25 MC (marker).

Curve shown on scope should be similar to the re-sponse curve shown in Figure 4. For proper setting ofthe pix carrier the 26.25 MC marker should appear onthe curve at a point approximately 50% of the verticalheight of the curve.

To obtain this setting retouch L8.

Reset RF signal generator frequency to 23.0 MC andretouch L301 and L7 for correct positioning of markeron curve.

Recheck setting of 26.25 MC marker to make sureThat position has not shifted on curve.

Disconnect bias battery.

Note: If the curve cannot be made to appear asabove due to a local station or other inter-ference, or if multiple markers appear, remove(VI - 6BZ7 or 6E307) RF tube from tuner.

TRAP ALIGNMENT

Connect voltmeter lead to Diode crystal rectifier asshown in Fig. 5. Connect Diode crystal rectifier betweenC.R. Tube Cathode lead (yellow wire) and chassisground. Signal generator is connected at junction ofL12 and C33. Set contrast control at maximum andvoltmeter to 3 volt scale (negative). Remove 6CB6 (V9)from socket. Use maximum output of generator at 4.5MC. Adjust LI, top of TR-3386 for minimum readingon meter.

When it is necessary to retouch this trap in the field,proper adjustment can be made by using the local sta-tion signal and turning the Fine Tuning Control to bringfine herringbone sound beat into the picture. The 4.5MC trap (LI) should then be adjusted to minimize thisbeat interference.

SOUND IF TRANSFORMER, (4.5 MC) ANDRATIO DETECTOR ADJUSTMENT

In view of the fact that the transmitted sound signalfrom a TV station is probably the most accurate avail-able, as far as frequency is concerned, it is recom-mended that a working signal be used for sound align-ment. The set should be connected to an antenna, turnedon, allowed to warm up for about 5 to 10 minutes andthen tuned for the best picture. A vacuum tube volt-meter should be connected to Pin 2-V4 and the meterset to the minus 30 volt scale. The bottom of the 4.5MC Sound IF Transformer (L2) and the primary of theRatio Detector (L4 - bottom of the chassis) should betuned for maximum deflection of the meter. The vacuumtube voltmeter should then be connected to the junc-tion of R7 and C6 and one side of the volume controland the secondary of the Ratio Detector (L3 - topadjustment) should be adjusted for a zero reading withthe meter set to the 3 volt scale. The secondary canalso be adjusted by ear tuning L3 for the eliminationof buzz in the sound.

92


OarAataloffeeeThe Packard -Bell television receivers described in this

manual incorporate either chassis type 2740 or 2940-1. Thetelevision portion is identical on each, but the 2940-1 chassisincludes a two tube standard broadcast tuner. All modelsuse a 21 inch rectangular electrostatic focus picture tube.

The following table indicates the type chassis and TVtuner used in the respective models.

VHF VHF/UHFTuner Tuner

(10534A) (10535C)Chassis

Type

Model 2742 2842 2740

Model 2743 2843 2740

Model 2744 2844 2740

Model 2941 3041 2940-1

PRODUCTION MODIFICATIONS:

The following modifications were made after productionof the receiver had begun and are listed to point out varia-tions in production from the schematics shown in thismanual. The reason for the change is shown in capitalletters.

A. INCREASE TONE CONTROL RANGE. In early productionof chassis 2740, capacitor C-11 was .005 mfd. Its valuewas changed to .01 mfd. This is the series capacitor inthe tone control section.

B. INCREASE AUDIO OUTPUT. Ratio detector transformer29068 was replaced by ratio detector transformer 29054.In connec-ion with this change, R-7 was changed from82 to 47C ohms, and a resistor R-97 (22,000 ohms, 1/2watt, 10%) was added between the screen of V-2 andthe low -B bus.

C. PREVENT REGENERATION IN MODELS USING VHF/UHF TUNER 10535C. (See Fig. 12).

1. Capacitor, ceramic, 5000 mmf, (23931) added as by-pass from R -F tuner filament terminal (C) to ground.

2. Capacitor, ceramic, 10,000 mmf, (23939) added asby-pass from 135 volt bus at power transformer toground. The ground lug of terminal strip must besoldered to chassis.

3. Capacitor, ceramic, 5000 mmf, (23931) added as by-pass from pin 4 to pin 7 of V-9, 4th Pix I -F.

4. Radio Frequency choke (29551) added between pin4 of V -B and pin 4 of V-9. These points were formerlyconnected directly together.

5. Resistor, 100 ohm, 1/2 watt, (73013) inserted betweenpin 6 of V-9 and tie point previously connected to t.

6. R-21, E dropping resistor to R -F tuner (4700 ohm2 watt; replaced by 5000 ohm 5 watt 10% resistor,

D. IMPROVE SOUND I -F SENSITIVITY. Resistor R-1, 10,000ohms, 1/2 watt, was removed from the receiver. Thisformerly was connected across the sound I -F inputcoil L-' .

MODELS WITH 2740 CHASSIS:IMPROVED PERFORMANCE IN FRINGEAND HIGH SIGNAL AREAS.

The addition of delayed AGC circuitry has been incor-porated in the production of these models. Improved per-formance will be noted in fringe areas, as evidenced byan increase in signal-to-noise ratio due to the RF amplifierbias beingheld near zero for low signal input.

High signal areas will benefit because of the muchgreater input signal now required to produce overload orcross -modulation effects.

Chassis incorporating this delay circuit can be identi-fied by the AGC control located on the chassis rear apronnear the horizontal drive control.

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If the delayed AGC circuit is added to a 2740 chassiscontaining a VHF/UHF (all -channel) tuner, the followingadditional changes must be made:

1. Add ground wire directly to chassis from pin 3(ground side of heater) on 2nd and 4th I -F tubes,V-7 and V-9.

2. Add ceramiccapacitor, 5000 mmf, part number23931, between pins 3 and 4 of 2nd I -F tube, V-7.

3. Also add a 5000 mmf capacitor, part number23931, between pin 6 of pix detector, V-10, andtuner side of 1 megohm isolation resistor in delayedAGC circuit.

COMPLETE REALIGNMENT IS NECESSARY UPON INSTAL-LATION OF DELAYED AGC.

(Circuit diagram on page 94, over.)

NOTE: TUBE LOCATIONS, TEST POINTS, AND ADJUST-MENTS ON THE 2740 AND 2940-1 CHASSIS ARE IDEN-TICAL EXCEPT THAT THE 2740 DOES NOT HAVE THESTANDARD BROADCAST (AM) TUNER.

NOTES

R-1 not used.

R-19 used on 2740, not used on 2940-1R-89 not used on 2740, used on 2940-1R-90 not used on 2740, used on 2940-1

C-15 is .01 mfd on 2740, .005 mfd on 2940-1.C-29 not used.

C-34 not used.

C-49 not used.

C-67 not used on 2740, used on 2940-1.

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PACKARD-BELL COMPANY MODELS 2742, 2743, 2744 &MODELS 2842, 2843, 2844, &

ALIGNMENT PROCEDUREGENERAL:

It is important that the service technician read and ad-here to the alignment instructions in this section. This is

especially important in the case of the picture I -F.

Some service technicians may be accustomed to aligningthe picture I -F response curve on the oscilloscope alone.This procedure is not recommended because it is actuallyquite possible to get what appears to be an acceptablecurve and still be lacking in horizontal resolution.

Instead, the spot frequency alignment outlined belowshould be followed.

In this procedure the sweep generator is fed in throughthe antenna terminals. The output impedance of the gener-ator must match the 300 ohm input impedance of the set.A matching network may be devised to accomplish this.Fig. 7 shows a network for a generator with 75 ohmsimpedance. If the generator impedance is 50 ohms changethe values to 56 ohms for the shunt resistor and 130 ohmsfor each of the series resistors.

Loose -coupling the signal generator to mixer tube (afterstep 10) is accomplished by disconnecting the tube shieldfrom ground and connecting the generator between theshield and ground.

Test point locations are shown on the schematics, Figs.17 and 18, and on the chassis illustration, Figs. 9,

75 OHMSSWEEP GENERATOROUTPUT IMPEDANCE

ANTENNATERMINALS300 OHMSBALANCED

Fig. 7. Matching Network

PICTURE I -F ALIGNMENT:

1. Remove ANI tube, 6AV6 (V-20).

2. Connect a 3 volt battery between point "A" andground, with the negative lead to point "A".

3. Connect a vacuum tube voltmeter between points "B"and "C", with the negative lead to point "C".

4. Remove I -F output plug from top of R -F tuner. Connectsignal generator to plug between center pin andshield, using a .001 mfd isolating capacitor. Connectgenerator ground to shield. Keep leads as short aspossible to prevent regeneration. Set generator outputat maximum.

Step

5.

Sig. Gen.Frequency

47.25 Mc.

6. 39.75 Mc.

Adjust

S-6 and S-13

S-8 and S-10

For

Minimum

Minimum

Adjust generator output for 2.5 to 3 volt VTVMreading for steps 7 through 12.

29413041

7. 41.25 Mc. S-12 Minimum

8. 42.50 Mc. S-11 and S-15 MAXIMUM

9. 45.35 Mc. S-14 MAXIMUM

10. 45.00 Mc. 5-9 MAXIMUM

REPEAT STEPS 5 THROUGH 10. Disconnect signalgenerator and replace I -F plug in tuner. Looselycouple generator to mixer tube (6J6) in R -F

tuner*, keeping leads short. (See general instruc-tions, above.)

11. 42.10 Mc. S-7 MAXIMUM

12. 45.75 Mc. S-20 MAXIMUM(S-20 is the I -F adjustment on R -F tuner)

13. Disconnect VTVM and 3 volt battery.

14. Connect oscilloscope to point "B", using a 22,000ohms isolating resistor in series with the scope probe.Connect an electrolytic capacitor, 5 mfd, 50 volt,between point "J" and ground, the negative leadgoing to point "J".

15. Connect sweep generator to antenna terminalsthrough an impedance matching network. (Seegeneral instructions, above.)

16. Rotate tuner to channel 3, and set sweep generatorto center frequency. With a sweep width of 10 Mc.,adjust generator output to develop approximately4 volts of A. G. C.

17. With signal generator loosely coupled to convertertube, adjust output to provide the markers shown onthe response curve, Fig. 8. Check the position of themarkers one at a time.

18. Observe the waveform obtained on the oscilloscope,and compare it with the waveform shown in Fig. 8.If the spot frequency alignment has been carefullydone, the comparison will be favorable. However,slight retouching of the I -F adjustments may be re-quired. It should not be necessary to change anyadjustment appreciably. The markers should be lo-cated as follows:

The 47.25 Mc., the 39.75 Mc., and the 41.25 Mc.markers at minimum response.

The 45.75 Mc. marker at 50% response.The 42.25 Mc. marker at a minimum of 50% re-sponse.

The 45.00 Mc. marker at 97% response.

The 45.00 Mc. marker must not exceed 97% responseor picture may smear on higher channels.

*In 82 -channel tuner, mixer tube is a 6U8.

95


PACKARD-BELL COMPANY

ALIGNMENT OF 4.5 Mc. TRAP:

1. Remove Pix Detector tube 6AL5, (V-10).

2. Connect signal generator between point "B" andground through a .001 mfd isolating capacitor.

3. Turn contrast control to maximum.

4. Connect an R -F vacuum tube voltmeter to point "D".If an R -F VTVM is not available, connect a germaniumdiode crystal in series with the positive probe of aconventional VTVM.

5. Set signal generator to 4.50 Mc., exactly, with theoutput at one volt or more.

6. Adjust trap, S-16, for minimum VTVM reading.

NOTE: If signal generator is not capable of one volt output,it will be necessary to adjust the trap visually. To do this,observe the picture and adjust the trap to eliminate the4.5 Mc. beat.

VOLUME A.N.I. 0

0 CONTRAST VERTLIN Vi

TONE SELECTOR

0 OoAM

TUNING

ANTENNATERMINAL

V-23

V-11

V-13

V-15

V-16

YOKE

V-18

V-17

Fig. 9. Chassis 2940-1, Top View

0 HEIGHT I

0 FINE TUNING\V FOCUS I I

00SC ADJ VERT HOLDC I I

0 BRIGHTNESS r4EIC'ITNC!;;1.

_I j

V-22

V-21

V-14 V-24 V-12

5-13

V-19 V-20 V-2

MODELS 2742, 2743, 2744 & 2941MODELS 2842, 2843, 2844, & 3041

SOUND I -F AND DETECTOR ALIGNMENT:1. Connect signal generator between point "8" and

ground through a .001 mfd isolating capacitor.2. Connect VTVM between points "E" and "F".3. With generator frequency at 4.5 Mc., and an FM

deviation of 7.5 Kc., adjust S-1, S-2, and S-3 forMAXIMUM output.

4. Connect AC voltmeter across speaker voice coil, andadvance volume control to obtain indication on meter.

5. Adjust Ratio Detector primary, S-4, for MAXIMUMoutput.

6. Connect VTVM between points "G" and "H".7. Adjust Ratio Detector secondary, S-5, for zero be-

tween positive and negative peaks.

SOUND47.25 MC. CARR/ER 4/.2. 5 MC. 39.75 MC.

R/CTURECARR/ER 50 %45.75 MC.

45.0 MC

50% M/A./.42.25 MC.

Fig. 8. I -F Response Curve

V-7 V-26 POINT "I"V-27 A M ANTENNA

LEAD5-20

S-9 5-7V-6

V-8

S-14

- S-4 AMV-9

5-5 A M

A M ANTENNALEAD

5-15

5-3 5-5 V-4V-5

V-10

5-1

V-1

V-3

96


PHILCOThe various models of Philco "B" and "C" line receivers (released to date

of publication) use several different chassis as listed below.

MODEL CODE CHASSISTUNER

PART NO.PICTURE

TUBEMODEL CODE CHASSIS TUNER

PART NO.PICTURE

TUBE

2204010 130 R181, DI81, D182 76-7664-2 21WP422C4124

{

300350

76-8946-176-8946-1

21YP4A21ZP4B

2204010 131 R181, D182 76-7664-2 21XP4 22C4I24L I 3503C0

350300

76-8946-176-8946-2

21ZP4B21ZP4B22C4010L 130 R181, D181, D182 76-7664-2 21WP4 22C4126 350 350 76-8946-2 21ZP4B22C4010L 131 5181, 0182 76-7664-2 21XP4 2204126L 350 350 76-8946-2 21ZP4B2204012 130 R181, D181 76-7664-2 21WP4 22C4310 300 300 76-8946-1 21YP4A2204012 131 R181, D181, D182 76-7669-2 21XP4 22C4310L 300 300 76-8946-1 2 IYP4A

22C4014 {131130

5181, D182R181, DI81, D182

76-7664-276-7664-2

21XP4A21WP4 2204312 350 350 76-8946-2 21XP4A

2204016 350 350 76-8946-2 21ZP4B 22C4312L 350 350 76-8946-2 21ZP4B

22C40I6L 350 350 76-8946-2 21ZP4B 2406010 354 354 76-8946-2 24VP4A

2204119 . 300 300 76-8946-1 21XP4 24C6109 354 354 76-8946-2 24VP4A

22C4120 300 300 76-8946-1 21YP4A 24C6109L 354 354 76-8946-2 24VP4A

22C4120L 300 300 76-8946-1 21YP4A 29C6110 354 354 76-8946-2 24VP4A

1 1337R181, D181, D182 76-7664-2 2IZP4B 24C6110L 354 354 76-8946-2 24VP4A2204122R181, D182 76-7664-2 21XP4A 2400112 354 354 76-8946-2 24VP4A

2204123 300 300 76-8946-1 21YP4A 2406310 354 354 76-8946.2 24VP4A

Material on R-181 and D-181 is published in SUPREME "1954 TelevisionServicing Information" manual, pages 87 to 97. The differences betweenD-181 and D-182 deflection chassis are explained below. Information onChassis 300 (and 301) is on pages 98 to 106, in this manual; while informa-tion on Chassis 350 and 354 is on pages 107 to 114. Look up the model youare servicing and refer to the correct chassis.

T3L801RFC

T I 0

R820

T460

R103

V18I B3GTHV

RECT.7

27_n_

T2 L804/06-0

RFC

TO ANODEOF CRT

DEFLECTION CHASSIS D-182Philco "B" line, code 131 television receivers

employ two chassis, RF chassis R-181, and deflec-tion chassis D-182. These chassis are the same asthe code 130 chassis (R-181 with D-181), withthe exception that an electrostatic focus typecathode ray tube and a different horizontal out-put transformer are employed. See Figure No. 1.

P7 17171--

T6 R8210815 L802

27K146

22.n.

T7 P3 I Y2

Ti

1808 1814

Y7L803

22.n.

P8 I Y3

HOR.YOKE

30 MH

L805949Q

Z A

8 7VI 7

6 A X4GTDAMPER

(Philco material is repro-duced through the courtesy ofthe Philco Corp.)

RFC

FIGURE I-HORIZONTAL OUTPUT TRANSFORMER CIRCUIT

97


Thetube usedTV -301

Thefocustransformer

Thenetic focusis shorted

General

checkingoscilloscope,thetablishedchannelquency,atobtainaligned,and

antennabeenthe

PHILCO TELEVISION TV -300 AND TV -301 CHASSIS

THE TV -300 AND TV -301 DIFFERENCE The TV -300 receiver contains a 13 position incremental

TV -301 is similar to the TV -300, the difference being in the pictureVHF tuner, covering VHF channels 2 through 13 with

Power and filament voltage for the UHFand the shorting out of one resistor in the TV -300 to make the adapter are supplied through a switch built into the

chassis. the VHF tuner. The output of the VHF tuner is aTV -300 chassis uses a 21XP4A picture tube which is an electrostatic IF signal which is inductively coupled to three stagger

tube. When this tube is used the 27 ohm resistor in the high voltage IF stages. A 1N64 crystal serves as the diode detectoris necessary for proper electrical centering of the picture. output of the IF stages.

TV -301 chassis uses a 21WP4A picture tube which is an electromag- The output of the video detector, a negative phase, composite-picture tube. When this picture tube is used the 27 ohm resistor video detected signal, is fed through a single video amplifier

out and the chassis is called the 301. to the cathode ray tube.

TELEVISION ALIGNMENT

The video -carrier intermediate frequency is 45.75 mc.,the sound intermediate (intercarrier) frequency is 4.5

The alignment procedure follows the general pattern of first Alignment of these circuits requires careful workmanshipthe tuner response with an FM sweep generator and good equipment. The following precautions must he observed:

comparing the response curve with that given in 1. There must be a good bond between the receiver chassismanual, and aligning the tuner if necessary. After it is es- and the test equipment. This is most easily obtained by having

that the tuner is in correct alignment, the video I -F the top of the workbench metallic. The receiver chassis shouldis aligned by tuning each coil to its assigned pole fre- be placed tuner -side down on the bench. If the bench hasusing an AM signal, and then feeding in a sweep signal metallic top, the test equipment and chassis can be bonded

the antenna terminals and retouching the I -F adjustments to a strip of copper about 2 inches wide. The section of the chassisthe desired pass band. Finally, the sound channel is nearest the tuner should rest on the strip.using an AM signal, by tuning the sound take -off coil 2. Do not disconnect the picture tube yoke, or speaker while

the I -F and ratio -detector transformers. the receiver is turned on.The over-all response curve (r -f, i-f) of the circuits ftom the HORIZONTAL OSCILLATOR ADJUSTMENT

terminals to the video detector, after the I -F stages havealigned, should appear essentially the same, regardless of 1. Center horizontal hold control.

channel under test. If not, the tuner should be aligned. 2. Adjust T-1 until the picture comes into sync.

TUNER OSCILLATOR ALIGNMENTTABLE 1

AM GENERATOR: Connect to the receiver antenna -input TP-2. Connect the scope ground lead to the chassis, nearterminals. (No matching network is required.) Use in TP-4.

modulated R -F output. RECEIVER CIRCUIT ALTERATIONS: Disconnect tuner AGC(white) lead from main chassis, and connect a 1.5 -volt

OSCILLOSCOPE: Connect the vertical -input lead, in series bias battery, with negative terminal to white lead fromwith a 1000 -ohm resistor, to the mixer plate test point, tuner, and positive terminal to chassis.

typea UHFposition.

tuner -rear of

40 Mc.,tuned

for the

andmc.and

noby

STEPAM GENERATORDIAL SETTING

RECEIVERTUNING

ADJUST REMARKS

1 257 Inc. channel 13 TC-506 for zero beat on scope. a. If regeneration occurs, increase bias;bias may be increased up to 4 or 5volts, if necessary.

b. Preset fine tuning control to centerof its range.

2 251 mc. channel 12 TG507 for zero beat on scope.

3 245 mc. channel 11 TG508 for zero beat on scope.

4 239 mc. channel 10 TC-509 for zero beat on scope.

5 233 mc. channel 9 TC-510 for zero beat on scope. a. To adjust channel 8 use channel 9tuning core, then recheck channel 9.

6 221 mc. channel 7 TC-511 for zero beat on scope. a. Repeat steps 1 thru 6 and readjustif necessary until channels are with-in 500 kc. of proper frequency.




98


PHILCO TV -300 & TV -301 CHASSIS

VIDEO I -F ALIGNMENTTABLE 2

A.M. GENERATOR: Connect to mixer test point, TP-2,through a mixer jig, and adjust the generator for approxi-mately 30% modulation at 400 cycles. Adjust the outputof the generator during alignment to keep the output atthe CRT cathode below 40 volts peak to peak.

SWEEP (FM) GENERATOR: After step 5 connect to antenna -input circuit through antenna -input matching network (seefigure ?)

OSCILLOSCOPE: Connect vertical -input lead to pin No. 11at the cathode ray tube.

PRESET: Contrast control full on. Channel selector to chan-nel position No. 1.

BIAS: Apply 5.0 volts of negative bias into TP-1 (AGCsystem).

NOTE: I -F shield must be in place.


SWEEP (FM) GENERATOR

ADJUST REMARKSSWEEP DIALSETTING

MARKER DIALSETTING

1 45.5 mc. Ti' for maximumindication on scope.

The scope level must not be per-

mitted to exceed 40 volts peak topeak or overloading will occur.

2 43.1 mc. VC -1 for maximumindication on scope.

3 42.7 mc. T -2 -IF for maximumindication on scope.

4 45.0 mc. T6 -IF for maximumindication on scope.

5 44.4 mc. T3 -IF for maximumindication on scope.

6

Channel 4(69 mc. with6 mc. sweepwidth).

kRunmareralong curvechecking againstcurve limitsgiven in figure 6.

If necessary retouchTT, VC1, T2 -IF,T6 -IF, T3 -IF.

Adjust carrier level with TT andT6 level curve with T-3. Position42.5 mc. slope with VC -1 and T-2.CAUTION: Retouch only slightly.

TUNER BANDPASS ALIGNMENT - See Table 3

RESPONSE MUSTFALL INSIDE SHADEDAREA

CHANNEL CARRIERSLIE DETwECM

THESE LIMITS

Fig. 2. Television tuner response curve,showing bandpass limits.

FRED FRED

50O

N

CENTER 50DESIRED ACTUALFREQUENCY / DESIRED

119 MC CENTER7C 70 FREQUENCY

75 MCAI

\I 0 100

i770ACCENTER

FREQUENCY

IA- CARRIERS

ORIGINAL

I 177.0CCENTER

FREQUENCY

/1.- CARRIERS -4

COMPENSATED

Fig. 3. Television tuner response curve, showing tracking compensation.

99



TUNER BANDPASS ALIGNMENTTABLE 3

SWEEP (FM) GENERATOR: Connect to receiver antenna -input circuit through antenna -input matching network (seefigure 1).

OSCILLOSCOPE: Same as in Chart 1.

RECEIVER CIRCUIT ALTERATIONS: Bias same as ChartI. Disconnect the tuner coupling link leads and connect a40- to 70 -ohm carbon resistor across the open end of thelead from the tuner.

STEP

SWEEP (FM) GENERATORRECEIVERTUNING

ADJUST REMARKSSWEEPDIAL

SETTING

MARKERDIAL

SETTING

t Channel 13(213 mc., with10-mc. sweepwidth.)

Channel 13

Set first to 210 mc.and not positionof marker onresponse curve.Then set to 216 mc.and note positionof marker onresponse curve.

Channel 13 Use oscilloscope gain as high as possiblewith respect to hum level and "bounce".Pips fix channel limits on curve. Responsecurve should be flat between limits (seefigure 2). If not, proceed with step 2.

2 213 mc.

213 mc.

Channel 13 T-8 - WS2 counter-clockwise until singlepeak appears.

CAUTION: Care must be taken not to unscrew core far enough to make it drop outof the coil.

3 Channel 13 Channel 13 T-15-WS3 until peakfalls on 213-mc. marker.

It may be necessary to increase sweep -generator output.

4

5

Channel 7(177 mc., with10-mc. sweepwidth.)

Channel 7

Set first to 174 mc.and note positionof marker onresponse curve.Set to 180 mc. and

position ofmarker onresponse curve.

Channel 7 Note curve with respect to tilt and centerfrequency. Curve should be centered inpass band and symmetrical. If not, pro -teed with step 5.

17.1 mc. & 180 mc. Channel 7 VC -3 and VC -2 to ob-min correct tilt on topof curve.

VC3 and VC2 compensate for the tuningeffect of Channel 13 adjustment upon Chan -nel 7. (See figure 3.)

6 Channel 13 213 mc. Channel 13 Retouch T-15 of WS3and T-8 - WS2 forsymmetrical response,centered about 213-mc.marker.

To retouch, only turn cores slightly.

7

8

Channel 7 117 mc. Channel 7 Repeat step 5. Check response curve for correct centerfrequency and symmetry.

Repeat steps 6 and 7. Repeat Channel 13 and Channel 7 adjust-ments, alternately, until favorable curvesare obtained on both.

9 Channel 6(85 mc., with10-mc. sweepwidth.)

Sct first to 82 mc.and note positionof marker onresponse curve.Then set to 88 mc.and note positionof marker onresponse curve.

Channel 6 Curve should be symmetrical and centeredin pass band. If not, proceed with step 10.

10 Channel 6 85 mc. Channel 6 T-14 of WS2 counter-clockwise until singlepeak appears.

CAUTION: Care must be taken not to un-screw core far enough to make it drop outof the coil.

11 Channel 6 85 mc. Channel 6 T-21-WS3 until peakfalls on 85-mc. marker.

It may be necessary to increase sweep -generator output.

12 Channel 6 85 mc. Channel 6 T-27 - WS5 for maxi-mum curve height andsymmetry of singlepeak.

After adjusting TC501, recheck as in step9. If necessary, reduce sweep -generatoroutput to avoid overloading.

13 Channel 6 85 mc. Channel 6 Retouch T-21 - WS3and T-14 - WS2 forsymmetrical response,centered about 85-mc.marker.


100

MOST -OFTEN -NEEDED 19SS TELEVISION SERVICING INFORMATIONPHILCO TV -300 & TV -301 CHASSIS

JIGS AND ADAPTERS REQUIRED

Mixer JigConnections to the grid of the mixer tube may be made

through the alignment jack provided for this purpose. To con-nect the generator to this point, a mixer -grid jig, Philco PartNo. 45-1739, and a connecting cable, Philco Part No. 45-1635,may be used. As an alternate, a Philco alligator -clip adapter,Part No. 45-1636, with as short a ground lead as possible, maybe used to connect the alignment jack. The ground lead shouldbe connected as close as possible to the mixer tube. It is es-sential that the signal -generator output lead be terminated witha 68 -ohm resistor (carbon), so that regeneration, caused byconnection of the lead to the mixer, is held to a minimum.

FINEaTUNING

VC.5, 13VC4

VC6

10

19 N9VC79evc. VC12

VC98 a._

071VC 6 VCII

VCI3

O

FRONT VIEW

T.2A

g

T-4.9)

_\\

5,-6

T-8

I

Antenna -Input Matching NetworkAn impedance -matching network for coupling the signal

generator to the antenna input terminals of the receiver is shownin figure I.

Fig. I. Antenna -Input Matching Network.

TP40TUNER POLE

0MIXER GRID

TP 2

512

CORRECT SLOPE OFWAVE FORM ONCHANNEL 7

O

O507

UHFPOWER

FUHF

INPUT

TOP VIEW

CHANNEL 13BAND WIDTH

TC504re -N

CHANNEL I --mg43.5MC GAIN TC5I8

TC505 TC503

CHANNEL 6BAND WIDTH

TC502

GAIN ON LOWCHANNELS

(0)TC501'

T -I

T-12

SIDE VIEW

13111.4-41M W 5

472,,,

G -r. I

isc.6

WS -3

Fig. 4. Tuner layout showing locations of adjustments.

9T- 0

P

TP-4

CD-L 9

2

4PLEL

L-19

L- I

7)

4G-5

G -7

yo'Vin

I F OUTPutCABLE

OR

Fig. 5. Tuner Wiring Diagram.

a

WS

w.g

22

TP-I

224 T

WS -5

S

T-26

ANT

kT-27

TAPERED LINE ASSY.

J

101



SOUND ALIGNMENTTABLE 4

A.M. GENERATOR: Connect the "hot" lead through a 2200ohm resistor to the junction of C-24, X3 and the xtaldet. Adjust generator for 400v. modulation at approxi-mately 30% modulation.

0a.

eNi 50ce

4

100

imiiiiiiim bli lanai111111011111111111101111111Rung rimmlusiirs1111111 1pp Al 1

NM III LIU:41111:91:11

111111114.41141

odd eihrip...k inufpli.. ... 1. ... /MEM II NM111011111111 P. 19111,111111111111IIMpiplilL11/1111111111111iblifilindilliiiiiidilliiiiii9111111111111 III lb 111111111

66 68.5 71

67.25 70.25VIDEO 50%

CARRIER CHECK POINTFREQUENCY IN MC

Fig. 6. Over-all R -F, I -F response curve,showing tolerance limits.

VOLTMETER: Use V.T.V.M. on 20,000 -ohms -per -volt volt-meter. Connect through a crystal probe to pin No. 11of the picture tube in step 1 and to pin No. 3 of the 6W6audio output tube in the remainder of the steps.

STEP

AMGENERATOR

DIALSETTING

ADJUST REMARKS

I4.5 mc.

modulatedT7 -IF for mini-mum indication.

Voltmeter throughxtal probe.Plate of videoamplifier.

24.5 mc.

modulatedT5 top for maxi-mum indication.

a. Volume controlfull on.

b. Voltmeter thruxtal probe to6W6 pin No. 3.

c. Keep generatorlevel low to pre-vent overload.

34.5 mc.

modulated

T5 bottom formaximum indica-tion.

4 4.5 mc.modulated

T4 -IF for maxi -mum indication.

Fig. 7. Base Layout - Top View - TV -300 Chassis.

102

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONPHILCO TV -300 & TV -301 CHASSIS

_00.04111011

Fig. 8. Composite Signal, Pin 2 of12BY7, 6 volts, 60 c.p.s.

Fig. 9. Composite Signal, Pin 2 of12BY7, 6 volts, 15,750 c.p.s.

OSCILLOSCOPE WAVEFORM PATTERN - TV -300

These waveforms were taken with the receiver adjusted for an approximate peak -to -peak output of 6 volts at the video detector. The voltages given with the waveformsare approximate peak -to -peak values. The frequencies shown are those of the wave-forms - not the sweep rate of the oscilloscope. The waveforms were taken with anoscilloscope having good high -frequency response. With oscilloscopes having poorhigh -frequency response, the sharp peaks of the horizontal waveforms will be morerounded than those shown, and the peak -to -peak voltages will differ from those shown.

Fig. 10. Video Amplifier Plate, 83 volts,60 c.p.s.

Fig. 11. Sync Separator Grid, Pin 2, 90volts, 60 c.p.s.

Fig. 12. Sync Separator Plate, Pin 1, 30 Fig. 13. Vertical -Oscillator Grid, Pin 7, Fig. 14. Vertical -Output Grid, Pin 2, 72volts, 15:750 c.p.s. 140 volts, 60 c.p.s. volts, 60 c.p.s.

Fig. 15. Vertical -Output Plate, Pin 9, Fig. 16. Phase Comparer, Pin 6, 7 volts, Fig. 17. Horizontal Oscillator, junction900 volts, 60 c.p.s. 15,750 c.p.s. of L800 and R806, 43 volts, 15,750 c.p.s.

Fig. 18. Horizontal -Oscillator Cathode,Pins 3 and 8, 18 volts, 15,750 c.p.s.

Fig. 19. Horizontal -Oscillator Grid, Pin Fig. 20. Horizontal -Output Grid, Pin 5,2, 40 volts, 15,750 c.p.s. 120 volts, 15,750 c.p.s.

103


490

oo I

CX1.1---1 1r Pry

T29SOO

OraR19II

V

T 13

C3

Rt1ra

C11

MCI

X2Oa'

WS -5

L-11

C2 1 C3IISO

=

-"'"

AUDIO

S-9

R39

IAll

TUNER

T P 4

SACK

WS 4

IC 10Ts

TP2rt ST

VC

C

74.. ss

12-

(41 X 8)

R322.

$. 12

=L9MOO

rldwo. W10.

TI

Ron?

WS-I

cs. C13

10

VC1

1111010

tOrrICTIONAT 21111

eoe

L-12

120

Iswv

R11

WS -IA

ISO

BACK

Voltage readings taken with a Philco Modal No. 7001: VTVM. All capacity values in micro-microfarads unless otherwise noted. Direction of arrow through control arms indicatesclockwise rotation. All capacitors so marked are of ceramic disc type. Capacitors markedGMV have tolerance of -0% +100%. Letters on tuner switch waters read from front toback of tuner. All resistors are V2 watt 10% unless otherwise noted. Resistance valuesnoted for coil and transformer windings are D.C. readings.

IF

%4

6055is. ,tiF

S6

32

CISco

933 erro%

.0o.

20%

.00020%

SAW.

92447.

.0 21

mergr

SYNCS12 b R54

jI ITAI7SI. Ur

ISO

C 40

12 2 Az

C41 r.nn 10.1

CI0114,4,00.0

PT

Sr

C 2

POWER SUPPLY

R2

10

R224.7 WO

mnf.

Con

104

I MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION

rT5

J1.7L

004W04021k

S -10R26

.20

E

1. 12*,

R27

535

350

R 2 3

C 20V9

1500

V01:2002505

006, 20%

5-10§-TA

1400& 642 022AT

C25.055.0

15.4r

R2910216201

C 36

21012

5-11

6AUDIO 0'1.114121

R47

1:C35

845114.20

4

0004

OT

sr a

521.

5-7202. v1E

T16

C2920

20;

s -e

X

OCO

C30" R25 zo,.

R34 R42 R46530 350 .1000

R35

20* --

C27Q820;

64

XTL

X3

T1C22 7000 Sown

o 111. y4,(022I I

C3

6 60

S-1312707

2,010 OUTPu

C37.124131+200

837

R4

C321020200

8140

003

40

:49

tox C 45 42o

R621. ',..14.11.R 60

a 14[2 R59-R58 CO ,,, 116I

o 2 24.4

2025 YrZOOV''

R5370%

000

c

x9

85

CO&NRAST

5. C44.Ire 8;

R63oR

150 01, x6

riff%ReC

R56NAA

R64,... 04(2220 2

4122En

VR82240 100

101 10100210.23

E -I

t 5060

111-2- 260V

VIDEO

R55R15

Hoe R1455.

12 B57 S3VERT OSC

v2111 01.Troa

C 124002

006910

DUO

C13-

25ooIevon

jMD 37e'

2.21 'L7rUR0020

713 '

U R 5302 TR66

/ TO 2

T -I X19220S4

R16

1000

Is. CI7 i?.607NOR 051.

Cie3251

820410

R4RIO

V0O1).--k 11010

C9.00.SO,

17 R19560

2224220 Tf. 21

C11

400+

R8114CA

20

C6

VR2 VERTICAL SWEEP2.35

VOT

L'noRio

407 1 v51111

r0

I000

26/1.0)

lsna

O

15-R3

C4

46,14 gat

S-5

48060110111. 0111701

VR3

HORIZONTAL SWEEP

8-1

. 01,510- 111.0

FC- I 621La. e . :see .1

oilRn".

E - I

04001,

0 .3.0350V

1TE

T...2.0v 07

8375 V

3.3

10611 to0110

S -14183 01N V RECO

E3

Re

225:

Fig. 21. Schematic Diagram - TV -300 Chassis.

105


PRIMO SERVICE MANUAL TV -300 & TV -30I CHASSIS

riv,,-, rivR -2 [1VR-3 0 n n ilLC

°14 ... 2aL__

I& . G -IFC

ics 0 13 E,-, fOlk*a_ ' II51-3)() 100 1

t, 1C ® ICI -

PT. ® 3)bras

4-2 0c) ,-gEit,B3 Ct. ®

I I

re 6; tol. R-7

} A k i o 3 4 0(2)1,,, . . . .4 Ia C-541P"'"°Ir e....\,....z:::

E -IV Ze.

'''' 8-4-

4

fij 1 C -I0.2\ ,.. -9 14 -gn l/ onCL -1 ict.,..:!.. '4,, cf 2=-, e 0

C II

m:3)4

4

4 ,14.

- d'.1)

474

,

, 1+ ilt 16R CL -1, IP r-Imito li .ci : -.. .. 6 7 8

MD Pc --41 C 19..,;, B 6b

, )CL -4 G-71

Joz .

' G-6 z 4 EV,r4tV" ,

c e x-"" CI r 1! s ®

. :. A

1.

VC -I

(-1 let 6) i)..4 a Am ,T,N 4'

'.!, .- " 1 °:,- 147. " al e? 4

_ . 0.. pa ; j '' - (27C_,

, Owi 46

7s

kli-'34

B -ti-, B-8 "6 ,...,,,.,

C'37 /49,

S -I2 8i ..11)

3 I,

Am.41 reSaMI

!

lig06, 5_13

.1 ,,Elosa, 01Ti CL -6I 8-9- -C3CL-7 . el

Ja.

_

2

ill," AB'. in

13

-lo

virV

G -I2

3( c1.- E-3te.A

L IVR-4 L IvB-s L hiR-6 LivR-7 L.NR-8

Fig. 22. Wiring Diagram, Bottoert View - TV -300.

1 TURNS

_,\ ' .,.....\--

...,

Etlib '4.2i TURN1

11-11112N5

1

liTURNS-' -. '- ''- --.

- -- -.% Ill ' ji

) + DAL ICORO

_--- - ---k- Ilr4----251" 1. \ i

.....=.DIAL COR WA" \\ ,..- - - -- DIAL CORD'S

Fig. 23. Dial Cord Stringing Arrangement.

106


PHILCO TELEVISION TV -350 AND TV -354 CHASSIS

CIRCUIT DESCRIPTION OF TV -354

The TV -354 is the same as the TV -350 with the followingexceptions. The vertical output tube has been changed from a6S4 to a 6CM6. The horizontal output tube from a 6BQ6 to a6CD6. The damper tube in the TV -350 is a 6AX4, while the

damper tube in the TV -354 is a 6AU4GT. The power supply inthe TV -354 contains two 5U4G rectifiers. These changes havebeen made in the TV -354 to accommodate the larger picturetube.

HORIZONTAL -OSCILLATOR ADJUSTMENT

To adjust the horizontal -oscillator circuit, tune in a stationand proceed as follows:1. Reduce the width of the picture until approximately 1 inchof blank screen appears at the right-hand and left-hand sidesof the picture.2. Increase the BRIGHTNESS control setting until the blank-ing becomes visible. This will appear as a dark vertical baron each side of the picture.3. Connect a .1 mf condenser from the test point to ground.(The plate side of the horizontal ringing coil, T1, is connectedto the test point.)4. Set the HORIZONTAL HOLD control to the approximatecenter of its mechanical rotation.5. Adjust the HORIZONTAL HOLD CENTERING controluntil equal portions of the blanking bar appear on both sidesof the picture.6. Remove the .1 mf condenser from the test point.

7. Adjust the horizontal ringing coil, T1, until equal portionsof the blanking bar again appear on both sides of the picture.

8. Rotate the HORIZONTAL HOI.D control through itsrange. The picture should fall out of sync on both sides of thecenter of its rotation. If the picture does not fall out of sync

10K SOUNDCROSSOVER

BIAS 14 V

TOP VIEWOF PLUG

C+ -SCOPEGROUND

-C- BIAS -14 V

iii i'

4 1 5 2 3SOLDEREDTO SHELL

1500 111.1, F

TO OSCILLOSCOPE

C+

SCOPEGROUND

TO OSCILLOSCOPE

15K,1/2 WATTPART NO.66-3158340

10K, 1/2 WATTPART NQ 66-3108340MINIATURETUBE SHIELDPART NO. 56-5629FA3

SHELLPART NO. 56-1146-I5 PIN PLUGPART NO. 27-4785-3

Fig. 2. Video I -F Alignment Jig(Video Test Jack Adapter No. 1).

O

5 50

TO

on both sides, readjust the HORIZONTAL HOLD CENTER.ING control.

9. Rotate the HORIZONTAL HOLD control through itsrange, and observe the number of diagonal blanking bars thatappear just before the picture pulls into sync. The pull -inshould occur with from 1 to 2 diagonal bars when the syncposition is approached from either direction. If proper pull -inis not obtained, repeat the above procedure.

ADESIREP

LEAD "A"

TOP VIEWRI

2 2200

10.000

PART NO.66-3108340

BIAS -14V

SHELL PART NO56-1146-I

IREO

PART NO66-2228340

fUSE ONLY FORALIGNMENT OF4.5 MC SOUNDTRAP ITC 301)

TO SIGNAL GENOR SCOPE

(SHORT LEAD) BIAS +


1500PART NO.62-215001001

SOUND CROSSOVERBIAS -I4 V

LEAD 'A"


SOLDER TO SHELL

(SHORT LEAD/ BIAS+


PLUG PARTNO 27-4785-3

Fig. 3. Sound I -F Input Alignment Jig(Video Test Jack Adapter No. 2).

IICENTER

ER10uENCV

CORNERS

ORIGINAL

UL

FREO

COMO:: NEAT CO

'-"COO

Fig. 5. Television tuner response curve, showing tracking compensation.

107



TUNER OSCILLATOR ALIGNMENTTABLE NO. 1

AM GENERATOR: Connect to receiver antenna -input ter-

minals. (No matching network is required.) Use un-

modulated r -f output.

OSCILLOSCOPE: Connect the vertical -input lead, in series

with a 1000 -ohm resistor, to the mixer grid test point.

Connect the scope ground lead to the chassis, near thetest point.

RECEIVER CIRCUIT ALTERATIONS: Disconnect tuner a -g -c(white) lead from main chassis, and connect a 1.5 voltbias battery, with negative terminal to white lead fromtuner, and positive terminal to chassis.


RECEIVERTUNING ADJUST REMARKS

1

2

257 mc. channel 13 VC4 for zero beat on scope. a. If regeneration occurs, inject bias;bias may be in. -<-:,sed up to 3

volts, if necessary at pin 1 videotest jack - TS1.

b. Preset fine tuning adjustment sothat it is in the middle of itsrange.

251 mc. channel 12 VC5 for zero beat on scope.

3 245 mc. channel 11 VC6 for zero beat on scope.





8 64.5 mc. channel 6 VC11 for zero beat on scope. 2nd harmonic gives 129 mc.



106 OHMS

SIGNAL GENERATOROUTPUT

(75 OHMS)106 OHMS

300 TOOHMS ANTENNA

INPUT

150 OHMS

Fig. 1. Antenna -Input snatching network.

RESPONSE MUSTrLL SIDE SNROCOARE A

NNE CARRIERS;.CSLi( 611 WC C N

C,& 'S

Fig. 4. Television tuner response curve,showing band pass

VC5V4

VC612 C-

,009VC7

9evceVC9

a

VC

FRONT VIEW

FINETUNING

TP40TUNER POLE

MIXER GRID_TP2r5)

n512

CORRECT SLOPE OFWAVE FORM ONCHANNEL 7

TOP VIEW

TC504

CHANNEL I ..4g43 5MC GAIN Tcsig

TC 505

CHANNEL 6BAND WIDTH

CHANNEL 13BAND WIDTH

TC503

TC502

GAIN ON LOWCHANNELS

CCOTC501

SIDE VIEW

Fig. 6. Tuner Layout.

1

UHFINPUT

108

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONPHILCO TV -350 & TV -354 CHASSIS

TUNER BANDPASS ALIGNMENTTABLE NO. 2

SWEEP (FM) GENERATOR: Connect to antenna -input circuitthrough antenna -input matching network (See figure 1).

OSCILLOSCOPE: Connect the vertical -input lead, in series witha 1C00 -ohm resistor, to the mixer plate test point, TP4.Connect scope ground lead to the chassis, near TP4.

RECEIVER CIRCUIT ALTERATIONS: Disconnect tuner a -g -c(white) lead from main chassis, and connect a 1.5 voltbias battery, with negative terminal to white lead fromtuner, and positive terminal to chassis. Disconnect tunerlink from terminal board, B-9, and connect a 40 to 70 -ohmcarbon resistor across the link.

STEP

SWEEP (FM) GENERATOR?ECEIVERTUNING ADJUST REMARKSSWEEP DIAL

SETTINGMARKER DIAL

SETTING

1

2

channel 13(213 mc. with10-mc. sweepwidth.)

Set first to 210 rile. andnote position of mark-er on response curve.Then set to 216 mc.and note position ofmarker on responsecurve.

channel 13 Use oscilloscope gain as high aspossible with respect to hum leveland "bounce". Pips fix channel li-mits on curve. Response curveshould be flat between limits (seefig. 5). If not, proceed with step 2.

channel 13

---213 mc. channel 13 TC502 counterclockwise un-

til single peak appears.--- - -

CAUTION: Care must be takennot to unscrew core far enough tomake it drop out of the coil.

3

4

5

channel 13 213 mc. channel 13

channel 6

channel 6

TC504 until peak falls on213 mc. marker.

_

It may be necessary to increasesweep -generator output.

channel 6(85 mc. with10-mc. sweepwidth.)

Set first to 82 mc. andnote position of mark-er on response curve.Then set to 88 mc.and note position ofmarker on response

Curve should be symmetrical andcentered in pass band. If not, pro-reed with step 5.

channel 6 85 mc. TC.503 counterclockwise un-tit single peak appears.

CAUTION: Care must be takennot to unscrew core far enough tomake it drop out of the coil.

6 channel 6 85 mc. channel 6 TC505 until peak falls on85 mc. marker.

It may be necessary to increasesweep -generator output.

7-

channel 6 85 mc.-channel 6 TC503 for maximum curve

height and symmetry of singlepeak.

After adjusting TC503, recheck asin step 4. If necessary, reducesweep -generator output to avoidoverloading.

8 channel 6 85 mc. channel 6 Retouch TC503 and TC505for symmetrical response, cen-tered about 85 mc. marker.


9 channel 1

(UHF)44 mc. channel 1

(UHF)Retouch TC503 and TC505for symmetrical response cen-tered about 44 mc.

After this adjustment recheck than -nel 6 and be sure it is within limits.

NOTE: On channel 7, observe the tilt and center frequency ofthe response curve. The curve should be centered on the passband and should be symmetrical. If it is not symmetrical, andappears unbalanced, as in figure 6, adjust C507 and C512 (figure5) to obtain a response curve which is in the mirror image

(tilt in the opposite direction) of the original: for example, ifchannel 7 response curve appears as in figure 6A, adjust C507and C512 until the curve appears as in figure 7B. This adjust-ment over -compensates to make allowance for the effect ofchannel 13 adjustments upon channel 7 response.

VIDEO I -F ALIGNMENT

AM GENERATOR: Connect to mixer test point, TP2, througha mixer jig, and adjust the generator for approximately30 percent modulation at 400 cycles. Adjust the output ofthe generator during alignment, to keep the output at thesecond detector below 4 volt, peak to peak.

SWEEP (FM) GENERATOR: After step 7, connect to antenna -input circuit through antenna input matching network. (Seefigure 1.)

OSCILLOSCOPE: Connect the vertical -input lead to the 15Kresistor of the video i-f alignment jig. Connect scope

ground lead to the ground lead of the jig. Plug jiginto TS1.

PRESET: Contrast and Brightness controls fully counterclock-wise, and channel selector to channel 4. Adjust AGCswitch to normal position.

BIAS: Apply -14 volts of negative bias to pin 1 of videoi-f alignment jig; ground positive side of bias supply topin 3 of jig. (See figure 2.)

NOTE: If the i-f shield has been removed for repairs, it mustbe replaced before proceeding with the alignment.

109

MOST -OFTEN -NEEDED 19S S TELEVISION SERVICING INFORMATION


VIDEO I -F ALIGNMENT (Continued)TABLE NO. 3

STEPAM GENERATORAM

SETTING

SWEEP (FM) GENERATOR

ADJUST REMARKSSWEEP DIALSETTING

MARKER DIALSETTING

1 47.25 not used not used VC1 for minimum indication onscope.

It is necessary to keep the generatoroutput sufficiently high that a null in -

22 41.25 not used not used VC2 for minimum indication onscope.

dication may be observed on the os-cilloscope; however, avoid overloadingof the receiver by excessive signal.

3 45.4 not used not used TI' for maximum indication onscope.

Adjust the output of the AM generator,to keep the output at the second de-tector below 4 volt, peak to peak.4 45.4 not used not used T2 for maximum indication on

scope. (For convenience, the oscilloscope maybe calibrated for this purpose before -

5 43.0 not used not used VC3 for maximum indication onscope.

hand.)

6 42.7 not used not used T3 for maximum indication onscope.

7 44.4 not used not used T4 for maximum indication onscope.

8 not used channel 4(69 mc., with6-mc. sweep

width)

Run markeralong curve,checkingagainst thecurve limitsgiven infig. 7.

If necessary, retouch ri, T2, T3,& T4 as directed in REMARKScolumn.

CAUTION: Do not touch sett-ings of VC1 and VC2.

Set Fine Tuning Cam to referencepoint previously made in step 1 ofTable 1. If response curve does notfall within limits shown in fig. 7, re -touch Ti & T2 for proper level ofcurve at video carrier frequency; ad -just T4 to level top of curve and T3for proper slope of low -frequency sideof curve. CAUTION: To retouch,only turn the adjustments slightly, par-ticularly T2.

SOUND IF ALIGNMENTAM GENERATOR: Connect "hot" lead through a 2200 ohm

resistor to pin 2 of TS1, using the video i-f alignment jig.Connect ground lead of generator to ground lead of jig.

0

100

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CARRIER CHECK POINTFREQUENCY IN MC

Fig. 7. Over-all R -F, I -F response curve,showing tolerance limits.

VOLTMETER: Use v.t.v.m. or 20,000 ohms -per -volt voltmeter.Connect to sound test point.

OSCILLOSCOPE: Connect through crystal probe to cathode(pin 11) of picture tube.

STEP

AMGENERATOR

DIALSETTING

ADJUST REMARKS

1 4.5 mc. T7 for maximum in-dication on volt-meter.

Remove 1st video i-ftube, and adjust thevolume control formoderate speaker out-put.

2 4.5 mc. T5 primary (bottomof T5) for maxi-mum indication onvoltmeter.

_3 4.5 mc. T5 secondary (top

of T5) for maxi-mum indication onvoltmeter and mini-mum speaker out-put.

The point of maxi -mum meter indicationfor TC5 should alsobe the point of mini-mum speaker output.

4 4.5 mc. T8 for minimum in-dication as view onthe oscilloscope.

5 usestationsignal

T5 primary (bottomof T5) for mini-mum AM (noise orbuzz), using speak-er output for indi-cation.

Replace 1st video i-ftube, and tune in astation, setting finetuning control to Ob-tain a crisp picture,with a small amountof beat.

110



OSCILLOSCOPE WAVEFORM PATTERNS

These waveforms were taken with the receiver adjusted for an approximate peak -to -peak output of 3.5 volts at the video detector. The voltages given with the wave-forms are approximate peak -to -peak values. The frequencies shown are those of thewaveforms - not the sweep rate of the oscilloscope. The waveforms were taken witha oscilloscope having good high -frequency response. With oscilloscopes having poorhigh -frequency response, the sharp peaks of the horizontal waveforms will be morerounded than those shown, and the peak -to -peak voltages will differ from those shown.

Fig. 8. Video Detector Output, Pin 2 ofTS1, 3.5 volts, 60 c.p.s.

Fig. 9. Video Detector Output, Pin 2 Fig. 10. Video Amplifier Plate, Pin 7, Fig. 11. Sync Separator Grid, Pin 7, 38of TS1, 3.5 volts, 15,750 c.p.s. 83 volts, 60 c.p.s. volts, 60 c.p.s.

Fig. 12. Sync Separator Plate, Pin 5, 41volts, 15,750 c.ps.

1

Fig. 13. Vertical -Oscillator Grid, Pin 2, Fig. 14. Vertical -Output Grid, Pin 6,.34 volts, 60 c.p.s. 80 volts, 60 c.p.s.

Fig. 15. Vertical Output Plate, Pin 9, Fig. 16. Phase Comparer, Pin 2, 11 volts, Fig. 17. Horizontal Oscillator, 43 volts,1100 volts, 60 c.p.s. 15,750 c.ps. 15,750 c.p.s. test point.

Fig. 18. Horizontal -Oscillator Cathode, Fig. 19. Horizontal -Oscillator Grid, Pin Fig. 20. Horizontal -Output Grid, Pin 5,Pins 3 and 8, 18 volts, 15,750 c.p.s. 2, 65 volts, 15,750 c.p.s. 160 volts, 15,750 c.p.s.

111


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Voltage readings taken with a Philco Model No. 7001: VTVM. All capacity values in micro-microfaracis unless otherwise noted. Direction of arrow though control arms indicates clockwiserotation. All capacitors so marked are of ceramic disc type. Capacitors marked GMV havetolerance -0% +100%. Letters on tuner switch wafers read from front back of tuner. Allresistors are V2 watt 10% unless otherwise noted. Resistance values noted for coil and trans-former windings are D.C. readings. Mica and ceramic capacitors are ±10% unless otherwisenoted.

Fig. 25. Schematic DJ

112

I MOST -OFTEN -NEEDED 195S TELEVISION SERVICING INFORMATION

PHILCO Schematic TV -350 Chassis

.IMP 2000

C42

R8410020%

.047 tarC62

AUDIO

VR82500

CONTROL

R35

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- TV -350 Chassis.

113

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONPHILCO

Fig. 23. Wiring diagram, bottom view - TV -350 chassis.

TV -350 & TV -354 CHASSIS

Fig. 24. Dial cord stringing arrangement (TV -350 & TV -354).

114


RCAVICTORMODELS

24-S-529, 24 -S -529U24-S-531, 24 -S -531U24-S-532, 24 -S -532U

Chassis Nos. KCS84F, KCS84H, KCS84J or KCS84K

MODELS

24-T-420, 24 -T -420U

24-T-435, 24 -T -435UChassis No. KCS84C or KCS84E

Models 24S529, 24S531, and 24S532, use Chassis KCS84F or KCS84J whichemploy VHF tuner KRK-22D. The exact circuit for these sets is published in thismanual. Chassis KCS84H and KCS84K are identical to other chassis except thata combination VHF -UHF (KRK-30D/E) tuner is used. These chassis are used inModels 24S529U, 24S531U, and 24S532U.

Models 24T420 and 24T435 use Chassis KCS84C which is practically identicalto KCS84F. Models 24T420U and 24T435U use Chassis KCS84E which is practicallyidentical to KCS84H.

PICTURE I -F TRANSFORMER ADJUSTMENTS. -Connect the i-f signal generator across the link circuit on

terminals A and B of T104.Connect the "VoltOhmyst" to the junction of R123 and

C142. Turn the AGC control fully clockwise.Obtain two 7.5 volt batteries capable of withstanding

appreciable current drain and connect the ends of a 1,000ohm potentiometer across each. Connect the battery positiveterminal of one to the chassis and the potentiometer arm tothe junction of R123 and C142.

Set the bias to produce approximately -5.0 volt of bias atthe junction of R123 and C142.

Connect the "VoltOhmyst" to the junction of R135 andL102 and to ground.

Set the VHF signal generator to each of the following fre-quencies and peak the specified adjustment for maximumindication on the "VoltOhmyst." During alignment, reducethe input signal if necessary in order to produce 3.0 volts ofd -c at R135 and L102 with -5.0 volts of i-f bias at the junctionof R123 and C142.

44.5 mc TI0845.5 mc T10743.0 mc. TI06

Set the VHF signal generator to the following frequencyand adjust the picture i-f trap for minimum d -c output atR135, L102. 47.25 mc. L118

SWEEP ALIGNMENT OF PICTURE I -F.-To align T1 and T104, connect the sweep generator to the

mixer grid test point TP2, in series with a 1500 mmf. ceramiccapacitor. Use the shortest leads possible, with not more thanone inch of unshielded lead at the end of the sweep cable.Connect the sweep ground lead to the top of the tuner.

Set the channel selector switch to channel 4.Clip 330 ohm resistors across terminals A and B of T107

and T108.Preset C122.to minimum capacity.Adjust the bias box potentiometer to obtain -5.0 volts of

bias as measured by a "VoltOhmyst" at the junction of R123and C142. Set the AGC control fully clockwise.

Connect a 180 ohm composition resistor from pin 5 of V106to terminal A of T106. Connect the oscilloscope diode probeto pin 5 of V106 and to ground.

Couple the signal generator loosely to the diode probe inorder to obtain markers.

Adjus' Tl (top) and T104 (top) for maximum gain andwith 45.75 mc. at 75% of maximum response.

Set the sweep output to give 0.3 volt peak -to -peak on theoscilloscope when making the final touch on the aboveadjustment.

Adjust C122 until 42.5 mc. is at 70% response with respectto the low frequency shoulder of the curve as shown in Figure23. Maximum allowable tilt is 20%.

Disconnect the diode probe, the 180 ohm and two 330 ohmresistors.

Connect the oscilloscope to the junction of R135 and LI02.Leave the sweep generator connected to the mixer grid test

point TP2 with the shortest leads possible.Adjust the output of the sweep generator to obtain 3.0 volts

peak -to -peak on .the oscilloscope.Couple the signal generator loosely to the grid of the first

pix i-f amplifier. Adjust the output of the signal generator toproduce small markers on the response curve.

Retouch T106, T107 and TI08 to obtain the response shownin Figure 24.

RATIO DETECTOR ALIGNMENT. -Set the signal gener-ator at 4.5 mc. and connect it to the first sound i-f grid, pin 1of V101.

Connect the "VoltOhmyst" to pin 2 of V103.Tune the ratio detector primary, T102 top core for maximum

d -c output on the "VoltOhmyst." Adjust the signal level fromthe signal generator for 6 volts on the "VoltOhmyst" whenfinally peaked. This is approximately the operating level ofthe ratio detector for average signals.

Connect the "VoltOhmyst" to the junction of R108 and C109.Tune the ratio detector secondary T102 bottom core for zero

d -c on the "VoltOhmyst."Repeat adjustments of T102 top for maximum d -c at pin 2 of

V103 and T102 bottom for zero d -c at the junction of R108 andC109. Make the final adjustments with the signal input leveladjusted to produce 6 volts d -c on the "VoltOhmyst" at pin 2of V103.

SOUND I -F ALIGNMENT. -Connect the signal generatorto the first sound i-f amplifier grid, pin 1 of V101.

Connect the "VoltOhmyst- to pin 2 of V103:Tune the T101 top core for maximum d -c on the "Volt-

Ohmyst."The output from the signal generator should be set to pro-

duce approximately 6.0 volts on the "VoltOhmyst" when thefinal touches on the above adjustment are made.

4.5 MC. TRAP ADJUSTMENT. -Connect the signal gener-ator in series with a 100 ohm resistor to pin 2 of V109. Set thegenerator to 4.5 mc. and modulate it 30% with 400 cycles. Setthe output to approximately 0.5 volt.

Short the third pix i-f grid to ground, pin 1, V108, to preventnoise from masking the output indication.

Connect the crystal diode probe of an oscilloscope to theplate of the video amplifier, pin 9 of V110.

Adjust the core 'of L104 for minimum output on the oscillo-scope.

Remove the short from pin 1, V108 to ground.

115

MOST -OFTEN -NEEDED 195S TELEVISION SERVICING INFORMATION

gli; RCA VICTOR

TUNER UNITKRK- 22 D

510FRONT

1

L53F.2.1

TRAP

1

1

L49 -

1.54I- FTRAP

SICFRONT

120

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SICREAR

L27126

L57I -F

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5

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LAS - 650.7A2609 R -F AMPL

133 VC15.41-4 ft L45 6,5

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TEST _ C13 C14 _POINTS T 270 270

V14.TPI

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76

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( 54 - 60 MC.)

COLOR CODES MOULDED PAPER CAPACITORS

MULTIPLIER

OUTER FOIL END(MAY BE ON EITHER END) (MAY BE ON OTHER ENO

MULTIPLIER

DIGITS TOLERANCE

VOLTAGERATING

DIGITS

OUTER FOIL END

VOLTAGERATING

:17;7TO OUTERFOIL ENO

Jam -TOLERANCE

MOLT !FLIER

RMA COLOR CODE, FIXED MICA CAPACITORS

WHITE INDICATES RMA STOSLACK INDICATES JAN STO

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WHITE INDICATES RMA STOBLACK INDICATES JAN STO

DIGITS DIGITS

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C175 '703T.047 -17.50

11770.1 5.59

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Z. 5.179V.R200

15K

8193330 K

IC

1181330 -IT-4

C162.01

61991506 R2o1

1.6 MEG

+270 V

The schematic is shown in the latestcondition at the time of printing.

All resistance values in ohms. K= 1000.

116


T102RATIO DET

TRANS4.5 MC

I .154

+4.11

R10747

R10410 K

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SC B6SRD. Po(

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CIRCUIT SCHEMATIC DIAGRAM ICCS84F OR ICCS841

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CI 59.00398172

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0105GAGS

AUDIOOUTPUT

V 110 A L1056X8 CI37 250 MU.I1VIDEO 47 0415.11211AmpL

11

19811. C118.0027

RI35 9

3900 C135 d --47 17.

1103250 RUN.GRN

V 11213

12AU7VERT SWEEP

oSc DISCO

3

6173

3.1HEIGHTcONTR.

C162 RI77.047 15 K

0160 R178

0.1 +2700

-C L109 C144WIDTH 180

V117

FIRS 6AU4.047 3 -GT

47 C190 1110 DAMPER270 15 mos

7

1C193 R136$.0035T ,20.=

8137 R13I2K 27K

+ 138 v.

16K)

R2I5

+270 V.

18,31g

T103AUDIOOUTPUTTRANS.

BLu

1

SPEAKER

A RED__C 119E120 NIT

+210V.

V1114

12AU7CI38 VIDEO

0.1 OUTPUT

225 V1106250

,E*

BLK BLK 7 12.50

214t470/1 814.4 0139

180 027

euNcrooN SW. Slot FRONT ANDREAR VIEWED FROM FRONT WITHCONTROL SHAFT IN MAN. COUNTERCLOCKWISE POSITION (P05.N0.1)

P05 I - TV. MIN HIGHS.I - TV NORMAL.3 TV. MIN. LOWS4- R1407.10. ',AM. HIGHS5- P1.1050. NORMAL6 _ PHONO. MIN. LOWS.

L106120 MU 1.1

BLU C1410.1

81405600 R1124

10KPIX.

CONTR.

V 113

R176 CI63 C167 8180 6A 0-SSWEEP

2215 .015 .027 2215 OUTPUT

C11 6110027 0164.022-481813315

cT.068

RI7912K

- 3 2

6146270

R17422 K

L107500 MU H

GRN.WRT

7500

.4270 V. la

CI24C30 MF.

,422015

+2700 R145200 K

BRIGHTNESSCONTR.

T112VERT. SWEEPOUTPUT TR.

1T5L711-

75VI -7

8152 4 3470N

17 1832.5 MEGVERT.LiNECONTR.

R185 +390K

R184390 K

VII6183-6T

RECT18.350V

R2I727K

C 188.047

820727K

Direction of arrows at controls indi-cates clockwise rotation.

61211

2530,

p102 -DEFLECTION YOKE PIN VIEW

RED

CI92 VERT. COILS I

120 1.113 L114 I

R2I3GRNtoo

R2II R212 I560 560

&K. RED

2

3

R,983300

V

rg7K

0118

24CP4AKINESCOPE

GLASSCOATING

CHANNELIND. LAMP

13RN

C 1690.1

0168047 R,89 IC170

157 1 10047

V119 V120

5U4 -G 5Y3-GTRECT RECT 1113

j102.FREARVIEW

ehC1194 CI17480 MF 100 MEI

GRN. HEW.

TEL 511

6R.VEL SA

B1

.270 VSUPPLY

W 108(1)5641

Sio3- INTE E1014

102

24-S-529, 24-S-53124-S-532

Figure 21 -Sound I -FResponse

4.5 MC

Figure 22 -Ratio Det.Response

42.5 MC70%

1154.60A,SUPPLY

45.75 MC75%75%

47258C

Figure 23-KRK22D

T1 and T104Response

Figure 24 -Overall I -F

Responsewith KRK22D

(For voltage information see the next three pages)

All voltages measured with "Volt-Ohmyst- and with no signal input. Volt-ages should hold within ±20% with117 v. a -c supply.

Schematic DiagramKCS84F or KCS84J

117


RCA Victor (continued)

TO ANTENNA TERMINALS

tsPEAKER CABLE

CHASSIS TOP VIEW

\"... .1*.

24-S-529, 24 -S -529U, 24-S-53124 -S -531U, 24-S-532, 24 -S -532U

6X805C 15

6BQ7A IMIXER7R.F AMP.

Tio2

RATIO0 DE7TRANS.

7115HIGH VOLTAGE TRANS.

//'4>

TIOB3912 PIX

1.F TRANS.

L1044.5 MC TRAP

0

710723F PIX

I -F TRANS.

TWAYET PIX

I.F TRANS.

VII212AU7ERT. 05C.DISCH 6

SYNC. OUT

7113POWER TRANS.

KINESCOPESOCKET

TIMIXERTRANS.)

5102, R1126 P. R1125LOCATED AS SHOWN HEREFOR MODELS 245531

248531U

CHANNELLAMP

5102

7 04 L118IV pm IN! PIXF GRID 1F GRID

TRANS TRAP0 0

CHANNELSELECTOR

SWITCH \

FINETUNINGCONTROL

5102 IR1122,10NOFF SWITCH

R112A1 L VOLUMEI CONTROLif -I-

I I 2II

' it -.7I R112A

RI128 I PICTURE

RI96NOR.

HOLD

R1961 :131I 1 R172- VERT

T HOLD

RI72 : 3 2t SPEAKER LEADS LOCATED L__J VERT

RIBS

HERE ON 215531 6 245531U LIN.

4 4R163 i 1

I

L__J R173

(\\ /,1 r----1 HEIGHT

RI731 ) 74

sq., 1

L.); ...---JSPEAKER '5,-",

CABLE sa,,/,

,..,.

'ii:,s16

.,...

II,0i34

P'S

s 1.1

5101n TVPHONO;F.T TONE SWITCHII d

5101:144'"

5102--1:II

1

8145 1

RIASBRIGHTNESS

R1I2APICTURE

I 7.-1 5102 P.R112BONOFFswiTCH

R"ZA & VOLUMECONTROL

POWER CORD

Chassis Top View (shown with KRK22D Tuner)

118


24-S-529, 24 -S -529U, 24-S-531 RCA Victor (continued)24 -S -531U, 24-S-532, 24 -S -532U VOLTAGE CHART

The following measurements represent two sets of conditions. In the first condition, a 15000 microvolt test pattern signal was fed into the receiver,

the picture synced and the AGC control properly adjusted. The second condition was obtained by removing the antenna leads and short circuit-

ing the receiver antenna terminals. Voltages shown are read with a type WV97A senior -VoltOhmyst- between the indicated terminal and chas-

sis ground and with the receiver operating on 117 volts, 60 cycles, a -c. The symbol < means less than. Balance of voltage charton the next page, over.

TubeNo.

TubeType Function

OperatingCondition

E. Plate E. Screen E. Cathode E. Grid

Notes onMeasurementsPin

No. VoltsPinNo. Volts

PinNo. Volts

PinNo. Volts

VI (V2)

KRK22D

orKRK3OD

(or E)

6BQ7AR -F

Amplifier15000 Mu. V.

Signal 6 170 8 0.1 7

No Signal 6 133 8 1.1 7 0

R -F

Amplifier15000 Mu. V.

Signal 1 270 3 170 2

No Signal 1 260 - 3 133 2

V2 (V1)

KRK22DorKRK3OD

( or E)

6X8 Mixer15000 Mu. V.

Signal 9 160 8 160 6 0 7-2.4 to-3.0

No Signal 9 145 8 145 6 0 7-2.8 to-3.5

R -F

Oscillator15000 Mu. V.

Signal 3 95 -- - 6 0 2-3.8 to

-5.5

No Signal 3 90 - 6 0 2-3.0 to

-5.1

V101 6AU61st SoundI -F Amp.

15000 Mu. V.Signal 5 122 6 138 7 1.01 1 0

No Signal 5 113 6 126 7 .95 1 0

V102 6AU62nd SoundI -F Amp.

15000 Mu. V.Signal 5 210 6 130 7 0 1 -2.05

*Unreliablemeasuring point.Voltage depends

on noise.No Signal 5 205 6 122 7 0 1 * - 1.12

V103 6AL5RatioDetector

15000 Mu. V.Signal 7 1.7 - - 1 21

7.5 kc deviationat 1000 cycles

No Signal 7 4.1 1 11.8 --RatioDetector

15000 Mu. V.Signal 2 1.7 5 21

No Signal 2 4.1 - - 5 11.8

V104 8AV61st AudioAmplifier

15000 Mu. V.Signal 7 78 - - 2 0 1 -.7 At min. volume

No Signal 7 76 - 2 0 1 -.65 At min. volume

V105 6AC)5AudioOutput

15000 Mu. V.Signal 5 205 6 220 2 15.2 1-7 0 At min. volume

No Signal 5 198 6 207 2 14.5 1-7 0 At min. volume

V106 6CF61st Pix. I -FAmplifier

15000 Mu. V.Signal 5 218 6 240 2 132 1 -8.2

*Unreliablemeasuring point.Make measure-ment at T104 -B.

No Signal 5 95.5 6 105 2 1.18 1 *<0.1

V107 6CF62nd Pix. I -FAmplifier

15000 Mu. V.Signal 5 222 6 243 2 <0.1 1 -8.45

No Signal 5 95.5 6 105 2 0.53 1 <0.1

V108 6CB63rd Pix. I -FAmplifier

15000 Mu. V.Signal 5 138 6 150 2 2.3 1 0

No Signal 5 130 6 143 2 2.2 1 <0.1

V109A 12AU7Picture2nd Det.

15000 Mu. V.Signal

-

1 -25.8 - 3 0 2 -1.85No Signal I -14 -- -- 3 0 2 -.6

119


RCA Victor (continued) 24-S-529, 24 -S -529U, 24-S-531VOLTAGE CHART 24 -S -531U, 24-S-532, 24 -S -532U

TubeNo.

TubeType Function

OperatingCondition

E. Plate E. Screen E. Cathode E GridNotes on

MeasurementsPinNo. Volts

PinNo. Volts

PinNo. Volts

PinNo. Volts

V109B 12AU7Horiz. SyncSeparator

15000 Mu. V.Signal 6 260 - 8 160 7 122

No Signal 6 253 - - -- 8 105 7 94.5

V110A 6X8VideoAmplifier

15000 Mu. V.Signal 9 120 8 147 6 .9 7 -1.85

AGC control set fornormal operation

No Signal 9 95 8 138 6 1.35 7 -.6AGC control set fornormal operation

V110B 6X8Vert. SyncSeparator

15000 Mu. V.Signal 3 79 6 .90 2 -26.8

No Signal 3 46.5 -- - 6 1.35 2 -2.1

VII1A 12AU7VideoOutput

15000 Mu. V.Signal 6 231 - - 8 13 7 0

No Signal 6 225 8 12.5 7 0

V 1 I 1 B 12AU7AGCAmplifier

15000 Mu. V.Signal 1 -55 - - 3 135 2 125

No Signal 1 0.3 - - 3 132 2 68,

V 112A 12AU7SyncOutput

15000 Mu. V.Signal 1 83 - -- 3 0 2 -3.28

No Signal 1 84 -- - 3 0 2 -1.3

V112B 12AU7VerticalOscillator& Discharge

15000 Mu. V.Signal 6 80 8 0 7 -63.5 of Vert. hold control

No Signal 6 182 - 8 0 7 -60Voltages shownare synced pix

adjustment

V113 6AQ5VerticalOutput

15000 Mu. V.Signal 5 253 6 262 2 0 1-7 -28.8

No Signal 5 245 6 253 2 0 1-7 -27.5

V114 6SN7GTHorizontalOsc. Control

15000 Mu. V.Signal 2 175 --- - 3 -3.5 1 -21

No Signal 2 170 - - 3 -5.5 1 -17.5

6SN7GTHorizontalOscillator

15000 Mu. V.Signal 5 183 - 6 0 4 -67

No Signal 5 179 -- - 6 0 4 -65

V115 6CD6GHorizontalOutput

15000 Mu. V.Signal Cap ' 8 193 3 22 5 -14

'High VoltagePulse Present

No Signal Cap 8 185 3 20.5 5 -13.5*High VoltagePulse Present

V1161B3GT;8016

H. V.Rectifier

15000 Mu. V.Signal Cap ' 2 & 7 18,700

*High VoltagePulse Present

No Signal Cap * - - 2 & 7 18,350 - *High VoltagePulse Present

V117 6AU4GT Damper15000 Mu. V.

Signal 5 261 - - 3 *


No Signal 5 253 - -- 3 *


V118 24CP4A Kinescope15000 Mu. V.

Signal Cap 18,700 10 428 11 44.5 2 0At averageBrightness

No Signal Cap 18,350 10 425 11 39.5 2 0At averageBrightness

V119V120

5U4G5Y3GT

Rectifiers15000 Mu. V.

Signal 4 & 6 - - - 2 & 8 277 -No Signal 4 & 6 - - 2 & 8 271

120


RCAVICTORTELEVISION RECEIVERS -MODELS

21 -S -501(U), 21-5-502(U), 21 -S -503(U),

21 -S -504(U), 21-5-505(U), 21 -S -506(U),

21 -S -517(U), 21 -S -518(U), 21 -S -519(U),

21 -S -521(U), 21-5-522(U), 21 -S -523(U),

21 -S -525(U), 21-5-526(U), 21 -S -537(U),

21-5-5251(U), 21-5-5252(U)Chassis Nos. KCS88B, KCS88C, KCS88D, KCS88E, KCS88J,

KCS88K, KCS88L, KCS88M, KCS88V, or KCS88VA

21-5-348K, 21-S-348KU, 21 -S -355K,

21-S-355KU, 21 -S -357K, 21-S-357KU,

21-5-362K, 21-S-362KU, 21-5-367K,21-S-367KU, 21 -S -369K, 21-S-369KU

(Continued below and on the next 7 pages)

The models listed at left without thesuffix "U" are for VHF reception.These models use Chassis KCS88B,KCS88C, KCS88D, KCS88E, KCS88V,with tuner unit KRK-22D. The modelswith the suffix "U" use Chassis KCS88J,KCS88K, KCS88L, KCS88M, or KCS88VA,with VHF -UHF tuner unit KRK-30, andthe circuit for these sets is included.

Chassis Nos. KCS88, KCS88A, KCS88F or KCS88H

Models 21S548 (Ch'assis KCS88N) and 21S548Uwith the television sections very similar to theModels 17S450, 17S451, and 17S453, useChassis KCS87 with tuner KRK-32. Thesesame numbered models with a suffix "U"use Chassis KCS87A with tuner KRK-30A.These are similar sets to the ones coveredin these pages, but use 17HP4 picture tubes.

PICTURE

ON -OFF& SO JNDVOLUME

I ZONTAL(FRED )

HORIZONTALDRIVE

VHFCHANNELINDICATOR

HE IGHT

UHFCHANNELINDICATOR

VHF FINETUNING &UHF TUNING

VHF CHANNELSELECTOR

VERTICAL UHF CHANGEOVERBRIGHTNESS HOLD SW TCH

VERTICAL TV - PHONOLINEARITY TONE SW ITCH

Receiver Operating Controls (UHF -VHF Models).

The models listed at left without thesuffix "U" use Chassis KCS88, KCS88A,which are very similar to Chassis KCS-88B. The models with the suffix "U"use Chassis KCS88F or KCS88H whichare similar KCS88J, but use tunerKRK-31 for combined VHF and UHFreception. In general, this servicematerial is applicable to all models.

(Chassis KCS88P) are combinationssets described on these pages.

ION TRAP MAGNET ADJUSTMENT. -Set the ion trapmagnet approximately in the position shown in Figure 3.Starting from this position immediately adjust the magnet bymoving it forward or backward at the same time rotating itslightly around the neck of the kinescope for the brightestraster on the screen. Reduce the brightness control settinguntil the raster is slightly above average brilliance. Turn thefocus control (shown in Figure 3) until the line structure ofthe raster is clearly visible. Readjust the ion trap magnet formaximum raster brilliance. The final touches of this adjust-ment should be made with the brightness control at the maxi-mum clockwise position with which good line focus can bemaintained.

ION TRAP

FOCUScONTWX

FOCUS MAGNETPOSITIONING ADJUSTMENT

CENTERINGADJUSTMENT

LEVER

* FOCUS CONTROL AND ION TRAP LOCATIONSON VERTICALLY MOUNTED CHASSIS.

Figure 3 -Yoke and Focus Magnet Adjustments

DO NOT INSTALL, REMOVE OR HANDLE THE KINESCOPE IN ANY MANNER UNLESS SHATTER-PROOF GOGGLES ARE WORN. PEOPLE NOT SO EQUIPPED SHOULD BE KEPT AWAY WHILEHANDLING KINESCOPES. KEEP THE KINESCOPE AWAY FROM THE BODY WHILE HANDLING.

121


RCA Victor (continued) 21-S-501 to 21-S-537 incl.INSTALLATION INSTRUCTIONS 21 -S -501U to 21 -S -537U incl.

DEFLECTION YOKE ADJUSTMENT.-If the lines of theraster are not horizontal or squared with the picture mask,rotate the deflection yoke until this condition is obtained.Tighten the knurled yoke adjustment nuts.

PICTURE ADJUSTMENTS.-It will now be necessary toobtain a test pattern or picture in order to make furtheradjustments.

When the Horizontal Oscillator and AGC System are oper-ating properly, it should be possible to sync the picture at thispoint. However, if the AGC control is misadjusted, and thereceiver is overloading, it may be impossible to sync thepicture.

If the receiver is overloading, turn R149 on the rear apron(see Figure 4) counter -clockwise until the set operates nor-mally and the picture can be synced.

CHECK OF HORIZONTAL OSCILLATOR ADJUSTMENT.-Turn the horizontal hold control' to the extreme clockwiseposition. The picture should be out of sync, with approxi-mately twelve bars slanting downward to the right. Turn thecontrol counter -clockwise slowly. The number of diagonalblack bars will be gradually reduced and when only 11/2 to3 bars sloping downward to the right are obtained, the pic-ture will pull into sync upon slight additional counter -clock-wise rotation of the control. The picture should remain in syncfor approximately two full turns of additional counter -clock-wise rotation of the control. Continue counter -clockwise rota-tion until the picture falls out of sync. Rotation beyond fall-out position should produce between 2 and 5 bars beforeinterrupted oscillation (motorboat occurs). Interrupted oscil-lation (motorboat) should be reached before full counter-clockwise rotation.

When the receiver passes the above checks and the pictureis normal and stable, the horizontal oscillator is properlyaligned. Skip "Adjustment of Horizontal Oscillator" and pro-ceed with "Focus Magnet Adjustment. -

OMITTED ON MODELS21-5-501(u), 21 -s -502M,6 21-5-518W)

Figure 4-Rear Chassis Adjustments

7104

ADJUSTMENT OF HORIZONTAL OSCILLATOR.-If in theabove check the receiver failed to hold sync over two fullturns of counter-cicckwise rotation of the control from thepull -in point, it will be necessary to make the following ad-justments.

Turn the horizontal drive trimmer C171 fully clockwise, thencounter -clockwise one full turn. Set the 'width coil L111 withthe stud flush with the inside edge of the chassis. Set the sinewave coil L121 fully counter -clockwise.

Adjustment of the horizontal frequency control in the coun-ter -clockwise direction will show a multiple number of barsbefore "motorboat" occurs. Adjust the sine wave coil L121until 3 or 4 bars are present before "motorboat" occurs,when the horizontal frequency control is rotated counter-clockwise from the fall out point.

If it is impossible to sync the picture and the AGC systemis in proper adjustment it will be necessary to align the Hori-zontal Oscillator by the method outlined in the alignmentprocedure on page

FOCUS MAGNET ADJUSTMENT. - The focus magnetshould be adjusted so that there is approximately three -eighths inch of space between the rear plate of the yoke andthe flat of the front face of the focus magnet. This spacinggives best average focus over the face of the tube.

The axis of the hole through the magnet should be parallelwith the axis of the kinescope neck with the kinescope neckcentered in the opening.

CENTERING ADJUSTMENT.-Centering is accomplishedby means of a separate plate on the focus magnet. The cen-tering plate includes a nut which must be loosened beforecentering. Up and down adjustment of the plate moves thepicture up and down and sidewise adjustment moves thepicture from side to side.

If a corner of the raster is shadowed, check the position ofthe ion trap magnet. Reposition the magnet within the rangeof maximum raster brightness to eliminate the shadow andrecenter the picture by adjustment of the focus magnet plate.In no case should the magnet be adjusted to cause any lossof brightness since such operation may cause immediate oreventual damage to the tube. In some cases it may be neces-sary to shift the position of the focus magnet in order toeliminate a corner shadow.

WIDTH AND DRIVE ADJUSTMENTS.-Set the horizontalcontrol at the -pull-in- point. Adjustment of the horizontaldrive control affects the high voltage applied tc the kine-scope. In order to obtain the highest possible voltage hencethe brightest and best focused picture, adjust horizontal drivetrimmer counter -clockwise until a bright vertical line appearsin the middle of the picture then clockwise until the bright

NOTE: Chassis designations with an "X" as the final letter (such asKCS88CX) use plate assembly Z102, instead of printed circuit PC102, forpicture IF section and are connected as shown below.

0 105 T1056CB6 2ND. PIA.

e,,,. F 1-F TRANS.AMPL. 43' MC'

3106 T1066CB6 3RD. FIX.2,10. I -F RANS.

45.5 MC.AMPL.

V107 T to7

6CB63RD PIX.1.0

AMPL.

4311 PIA.TRANS.CR101

44.5 MC. 2ND.060

811631 4

fN9

R120566

6

C121 _470'

_C 18001

:14! TgliNL118

CI23.00i

1211g4f.4;z:T

L1P3

!TIT -2 Mrs.001

C 125A

.001

8127ISO

e042513

3

C1279

0126001

Ci;028

C133470

8123ISO K

+280V.

110390.39

.2805. +112 V.

122


21-S-501 to 21-S-537 incl.21 -S -501U to 21 -S -537U incl. INSTALLATION INSTRUCTIONS

line just disappears.At maximum brightness adjust the width control L111 to

obtain correct picture width.Return the brightness to normal level and readjust the drive

trimmer C171 as before.Adjustments of the horizontal drive control affect horizontal

oscillator hold and locking range. If the drive control wasadjusted, recheck the oscillator alignment.

HEIGHT AND VERTICAL LINEARITY ADJUSTMENTS.-Adjust the height control (R165 behind front control panel)until the picture fills the mask vertically. Adjust vertical line-arity (R174 behind front control panel), until the test patternis symmetrical from top to bottom. Adjustment of either con-trol will require a readjustment of the other. Adjust centeringto align the picture with the mask.

FOCUS.-Adjust the focus control for maximum definitionin the test pattern vertical "wedge" and best focus in thewhite areas of the pattern.

Recheck the position of the ion trap magnet to make surethat maximum brightness is obtained.

Check to see that the knurled nuts of the yoke and focusmagnet and the focus magnet mounting nuts are tight.

CHA NNE LSELECTOR

KNOB

FINE TUNINGKNOB

TO REMOVE KNOBS PULLOUTWARD OFF SHAFT

OSCILLATOR ADJUSTMENTCHANNEL NUMBER

Figure 5-KRK22D R -F Oscillator Adjustments

KRK22D, OR KRK30 VHF R -F OSCILLATOR ADJUST-MENTS.-Tune in all available stations to see if the receiverr -f oscillator is adjusted to the proper frequency on all chan-nels. The adjustments for channels 2 through 12 are availablefrom the front of the cabinet by removing the station selectorescutcheon as shown in Figure 5 or 6. Adjustment for chan-nel 13 is on top of the Chassis. The oscillator for the UHF tunersection of the KRK30 tuner should be adjusted by the methodoutlined on page 14 under Alignment Procedure.

AGC THRESHOLD CONTROL.-The AGC threshold con-trol R149 is adjusted at the factory and normally should notrequire readjustment in the field.

To check the adjustment of the AGC Threshold Control, tunein a strong signal and sync the picture. Momentarily removethe signal by switching off channel and then back. If the pic-

VHF CHANNEL SELECTORS. UHF CHANGE OVER KNOB

UHF CHANNELIN. GATOR DIALft

.......,....-..

FINE TUNING& UHF TUNINGKNOB

TO REMOVE KNOBS AND UHFINDICATOR DIAL PULL OUT WARDOFF SHAFT

OSCILLATOR ADJUSTMENTCHANNEL NUMBER

Figure 6-KRK30 VHF R -F Oscillator Adjustment


ture reappears immediately, the receiver is not overloadingdue to improper setting of R149. If the picture requires anappreciable portion of a second to reappear, or bends exces-sively, R149 should be readjusted.

Turn R149 fully counter -clockwise. The raster may be bentslightly. This should be disregarded. Turn R149 clockwiseuntil there is a very, very slight bend or change of bend inthe picture. Then turn R149 counter -clockwise just sufficientlyto remove this bend or change of bend.

If the signal is weak, the above method may not work as itmay be impossible to get the picture to bend. In this case,turn R149 clockwise until the snow in the picture becomesmore pronounced, then counter -clockwise until the best signalto noise ratio is obtained.

The AGC control adjustment should be made on a strongsignal if possible. If the control is set too far clockwise on aweak signal, then the receiver may overload when a strongsignal is received.

FM TRAP ADJUSTMENT.-In some instances interferencemay be encountered from a strong FM station signal. A trapis provided to eliminate this type of interference. To adjustthe trap tune in the station on which the interference is ob-served and adjust the FM trap for minimum interference inthe picture. The trap is L53 on KRK22D or L5 or KRK30 tunersand is located on the antenna matching transformer.

CAUTION.-In some receivers, the FM trap L5 or L53 willtune down into channel 6 or even into channel 5. Needless tosay, such an adjustment will cause greatly reduced sensitivityon these channels. If channels 5 or 6 are to be received, checkL5 or L53 to make sure that adjustment does not affect sensi-tivity on these two channels.

Replace the cabinet back and connect the receiver antennaleads to the cabinet back. Make sure that the screws holdingthe back are up tight, otherwise it may rattle or buzz when thereceiver is operated at high volume.

KINESCOPE AND SAFETY GLASS CLEANING.-The frontsafety glass may be removed to allow for cleaning of thekinescope faceplate and the safety glass if required.

To do this, remove the rear panel of the receiver. Thereare several flat springs holding the front metal trim of thecabinet to the plastic kinescope mask.

Reach in from the rear of the receiver and press in on eachspring at the open end. Slide the spring out of the slot pro-vided. The front trim and safety glass should be held in posi-tion by another person to prevent its falling outward whenremoving the springs.

Remove the metal trim and the safety glass.The kinescope faceplate and the safety glass should only

be cleaned with a soft cloth and "Windex" or similar clean-ing agent.

Replace the metal trim, the cabinet rear panel and thesafety glass.

PICTURE I -F TRANSFORMER ADJUSTMENTS.-Connect the i-f signal generator, in series with a 1500 mmf.

ceramic capacitor, to the mixer grid test point TP2.Connect the -VoltOhmyst- to the junction of R118, R146 and

C120 and to ground. Turn the AGC control fully clockwise.Obtain two 7.5 volt batteries capable of withstanding

appreciable current drain and connect the ends of a 1,000ohm potentiometer across each. Connect the battery positiveterminal of one to the chassis and the potentiometer arm tothe junction of R118, R146 and C120. The second battery willbe used later.

Set the bias to produce approximately -4.0 volt of bias atthe junction of R118, R146 and C120.

Connect the "VoltOhmyst" to the junction of R129 andL103 and to ground.

Set the VHF signal generator to each of the following fre-quencies and peak the specified adjustment for maximumindication on the "VoltOhmyst." (Note: These transformersshould be peaked with their cores at the ends of the coilsnearest the chassis.) During alignment, reduce the input sig-nal if necessary in order to produce 3.0 volts of d -c at R129and L103 with -4.0 volts of i-f bias at the junction of R118,R146 and C120.

44.5 mc. T10745.5 mc. T10643.0 mc. T105

123

MOST -OFTEN -NEEDED 195S TELEVISION SERVICING INFORMATION

RCA Victor (continued)ALIGNMENT PROCEDURE

Set the VHF signal generator to the following frequencyand adjust the piciure i-f trap for minimum d -c output atR129, L103. Use sufficient signal input to produce 3.0 voltsof d -c on the meter when the adjustment is made.

47.25 mc. L102(Note: Core should be at end of coil nearest chassis when

properly adjusted.)

SWEEP ALIGNMENT OF PICTURE I -F.-To align the mixer plate circuit, connect the sweep gener-

ator to the mixer grid test point TP2, in series with a 1500mmf. ceramic capacitor. Use the shortest leads possible, withnot more than one inch of unshielded lead at the end of thesweep cable. Connect the sweep ground lead to the top ofthe tuner.

Set the channel selector switch to channel 4.Clip a 330 ohm resistor between pin 1 of V107 and ground.Preset C116 to minimum capacity.Adjust the bias box potentiometer to obtain -4.0 volts of

bias as measured by a "VoltOhmyst" at the junction of R118,R146 and C120.

Connect a 180 ohm composition resistor from pin 5 of V105to pin 6 of V105. Connect the oscilloscope diode probe to pin5 of V105 and to ground.

Couple the signal generator loosely to the diode probe inorder to obtain markers.

For Models Without Suffix "UnAdjust T1 (top) and 1104 (top) for maximum gain and with

45.75 mc. at 75% of maximum response.Set the sweep output to give 0.3 to 0.5 volt peak -to -peak on

the oscilloscope when making the final touch on the aboveadjustment.

Adjust C116 until 42.5 mc. is at 70% response with respectto the low frequency shoulder of the curve as shown in Figure9. Maximum allowable tilt is 20%.

Disconnect the diode probe, the 180 ohm and the 330 ohmresistors.

Connect the oscilloscope to the junction of R129 and L103.Leave the sweep generator connected to the mixer grid test

point TP2 with the shortest leads possible.Adjust the output of the sweep generator to obtain 3.0 to

5.0 volts peak -to -peak on the oscilloscope.Couple the signal generator loosely to the grid of the first


Figure 9--KRK22D

TI and T104Response

Figure 10 -Overall I -FResponse

with KRK22D

Retouch T105, T106 and T107 to obtain the response shownin Figure 10.

Increase sweep output ten times and check attenuation at41.25 mc. Adjust 1105 and 1107 to set 41.25 mc. between 25and 35 times down with curve as shown in Figure 10.

Move the sweep generator to the antenna terminals. Con-nect -3.0 volts bias to pin 5 of V103. Adjust T106 and T107.slightly to correct for any overall tilt while switching fromchannel to channel.

Instructions Applicable to "U" ModelsAdjust T2 (top) and T104 (top) for maximum gain and

with 45.75 mc. at 75% of maximum response.Set the sweep output to give 0.3 to 0.5 volt peak -to -peak

on the oscilloscope when making the final touch on the aboveadjustment.

21-S-501 to 21-S-537 incl.21 -S -501U to 21 -S -537U incl.

Adjust C116 until 42.5 mc. is at 70% response with respectto the low frequency shoulder of the curve as shown inFigure 11. Maximum allowable tilt is 20%.

Disconnect the diode probe, the 180 ohm and the 330 ohmresistors.

42.5MC70%

Figure 11-KRK30

T2 and T104Response

4575 MC75% ± 5%

42 5MC

Figure 12 -Overall

I -F Responsi.with KRK30

450MC90%

4575 MC-50%

42.5MC .45.75 M C

Figure 13-KRK30

L9 and C308I -F Response

Connect the oscilloscope to the junction of R129 and L103.Leave the sweep generator connected to the mixer grid test

point TP2 with the shortest leads possible.Adjust the output of the sweep generator to obtain 3.0 to

0.5 volts peak -to -peak on the oscilloscope.Couple the signal generator loosely to the grid of the first


Retouch T105, T106 and T107 to obtain the response shownin Figure 12.

Increase sweep output ten times and check attenuation at41.25 mc. Adjust 1105 and 1107 to set 41.25 mc. between 30and 40 times down with curve as shown in Figure 12.

To align the I -F amplifier circuit of the KRK30, connect theVHF sweep generator to the front terminal of the 1N82 crystalholder in series with a 1000 ohm resistor and a 1500 mmf.ceramic capacitor. Use the shortest leads possible, groundingthe sweep ground lead to the tuner case.

To do this, remove the crystal cover and connect the re-sistor, after insulating the lead with tubing, to the crystalfront terminal.

Set the UHF CHANGEOVER switch to the UHF position, andthe UHF TUNING between channels 68 and 69 at 800 mc.

Connect a 180 ohm composition resistor and a 1500 mmf.capacitor in series between test point TP3 and ground withthe capacitor connected to TP3 and the resistor to ground.

450MC Connect the oscilloscope diode probe to the junction between- 90 % the resistor and capacitor.

4575 MC Couple the VHF signal generator loosely to the diode probe- 50 % in order to obtain markers.

Connect the potentiometer arm of the second bias supplyto the AGC terminal on the tuner and ground the batterypositive terminal to the tuner case. Adjust the bias potenti-ometer to produce -3.0 volts of bias, as measured by the"VoltOhmyst" at the AGC terminal on the tuner.

Set the sweep generator to produce 0.5 volt or less peak -to -peak on the oscilloscope.

Adjust C308, on the UHF section, and L9, on the VHF sec-tion, of the tuner for maximum gain with 45.75 mc. and 42.5mc. markers as shown in figure 13.

If necessary adjust L27 to place the 45.75 mc. marker atthe peak of the curve. Adjust L43 for minimum tilt of the curveas shown in figure 13.

Remove the resistor, capacitor and diode probe from TP3and connect the oscilloscope to the junction of R129 and L103.Use 3.0v peak -to -peak on the oscilloscope.

Connect the VHF sweep generator to the antenna ter-minals. Keep the AGC bias at -3.0 V and the I -F bias at-4.0 volts.

Couple the signal generator loosely to the grid of the firstpicture I -F amplifier.

Switch through all VHF channels and check for propercurve shape as in figure 12. Retouch 1106 and 1107 slightlyto correct for any overall tilt that is essentially the same onall channels.

Disconnect the VHF sweep generator and connect the UHFsweep generator to the antenna terminals. Check on all UHFchannels for proper wave shape as shown in figure 12, re -

124

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATION21-S-501 to 21-S-537 incl.

21 -S -501U to 21 -S -537U incl.ALIGNMENT PROCEDURE

touching C308 and L9 if necessary to correct any overall tilt.Do not retouch T2, T104, T105, T106 or T107.Remove the sweep and marker generators and the bias

supplies.

RATIO DETECTOR ALIGNMENT.-Set the signal gen-erator at 4.5 mc. and connect it to the first video amplifiergrid, pin 7 of V108A, in series with a .01 mfd. capacitor.

As an alternate source of signal, the RCA WR39B orWR39C calibrator may be employed. In such a case, con-nect the calibrator to the grid of the third pix i-f amplifier,pin 1 of V107.

Set the frequency of the calibrator to 45.75 mc. (pix carrier)and modulate with 4.5 mc. crystal. The 4.5 mc. s,gnalwill be picked off at pin 9 of V108A and amplified throughthe sound i-f amplifier.

Connect the "VoltOhmyst" to pin 7 of V102.Tune the ratio detector primary, T102 top core for maximum

d -c output on the "VoltOhmyst." (Peak with core at end ofcoil away from chassis.) Adjust the signal level from thesignal generator for 5 volts on the "VoltOhmyst" whenfinally peaked. This is approximately the operating level ofthe ratio detector for average signals.

Connect the "VoltOhmyst" to the junction of R104 and C107.Tune the ratio detector secondary T102 bottom core for zero

d -c on the "VoltOhmyst." (Adjust with core at chassis endof coil.)

Repeat adjustments of T102 top for maximum d -c at pin 7of V102 and T102 bottom for zero d -c at the junction of R104and C107. Make the final adjustments with the signal inputlevel adjusted to produce S volts d -c on the "VoltOhmyst" atpin 7 of V102

SOUND TAKE -OFF ALIGNMENT.-Connect the signalgenerator to the first video amplifier grid, pin 7 of V108A.

As an alternate source of signal, the RCA WR39B orWR39C calibrator may be employed as above.

Connect the "VoltOhmyst" to pin 7 of V102.Tune the T101 top core for maximum d -c on the "Volt-

Ohmyst." (Peak with core at chassis end of coil.)The output from the signal generator should be set to

produce approximately 5 volts on the "VoltOhmyst" whenthe final touches on the above adjustment are made.

(Alternate Method for Ratio Detector andSound I -F Alignment)

Set the signal generator at 4.5 mc. and connect it to thefirst video amplifier grid, pin 7 of V108A in series with a .01mfd. capacitor.

Connect the "VoltOhmyst" to pin 7 of V102.Tune the ratio detector secondary TI02 bottom core for

maximum d -c on the "VoltOhmyst." (Peak with core at chassisend of coil.)

Tune the ratio detector primary, T102 top core for maximumd -c output on the "VoltOhmyst." (Peak with core at end ofcoil away from chassis.) Adjust the signal level from thesignal generator for 5 volts on the "VoltOhmyst" when finallypeaked, when making the above adjustments.

Tune the T101 (top) core for maximum d -c on the "Volt-Ohmyst." (Peak with core at chassis end of coil.)

The output from the signal generator should be set toproduce approximately 5 volts on the "VoltOhmyst" whenthe final touches on the T101 adjustment are made.

Connect the "VoltOhmyst" to the junction of R104 and C107.Tune T102 bottom for zero d -c at the junction of R104

and C107. (Make adjustment with core at chassis end of coil.)4.5 MC. TRAP ADJUSTMENT.-Connect the signal gen-

erator in series with a 1500 mmf. capacitor to pin 7 of V108A.Set the generator to 4.5 mc. and modulate it 30% with 400cycles. Set the output to approximately 0.5 volt.

Short the third pix i-f grid to ground, pin 1, V107, to preventnoise from masking the output indication.

Connect the crystal diode probe of an oscilloscope to theplate of the video output, pin 6 of V109A.

Adjust the core of L109 for minimum output on the oscillo-scope. (Make adjustment with core at chassis end of coil.)

Remove the short from pin 1, V107 to ground.As an alternate method, this step may be omitted at this

point in the alignment procedure and the adjustment made"on the air" after the alignment is completed.

If this is done, tune in a station and observe the picture onthe kinescope. If no 4.5 mc. beat is present in the picture,when the fine tuning control is set for proper oscillator-fre-

RCA Victor (continued)quency, then L109 requires no adjustment. If a 4.5 mc. beat ispresent, turn the fine tuning control slightly clockwise so asto exaggerate the beat and then adjust L109 for minimumbeat.

AGC CONTROL ADJUSTMENT.-Disconnect all test equip-ment except the oscilloscope which should be connected topin 6 of V109A.

Connect an antenna to the receiver antenna terminals.Turn the AGC control fully counter -clockwise.Tune in a strong signal and adjust the oscilloscope to see

the video waveform.Turn the AGC control clockwise until the tips of sync begin

to be compressed, then counter -clockwise until no compres-sion is obtained.

HORIZONTAL OSCILLATOR AND OUTPUT ALIGNMENT.-Normally the alignment of the horizontal oscillator is notconsidered to be a part of the alignment procedure, but sincethe oscillator waveform adjustment may require the use of anoscilloscope, it can not be done conveniently in the field.The waveform adjustment is made at the factory and nor-mally should not require readjustment in the field. However,the waveform adjustment should be checked whenever thereceiver is aligned.

Turn the horizontal drive trimmer C171 fully clockwisethen counter -clockwise one full turn. Set the stud of thewidth coil L111 flush with the inside rear edge of the chassis.

Place a jumper across the terminals of the sine wave coilL121 and adjust the horizontal (frequency) control until thepicture pulls into sync. Remove the short across the sinewave coil.

Connect the low capacity probe of an oscilloscope tothe junction of L120, L121 and R189. Turn the horizontal(frequency) control clockwise until the picture falls out ofsync, then counter -clockwise until the picture just pulls intosync. The pattern on the oscilloscope should be as shownin Figure 23. Adjust the sine wave adjustment core L121until the two peaks are at the same height. During this adjust-ment, the picture must be kept in sync by readjusting thehorizontal (frequency) control if necessary.

Figure 23-Horizontal Oscillator Waveforms

This adjustment is very important for correct operation ofthe circuit. If the broad peak of the wave on the oscilloscopeis lower than the sharp peak, the noise immunity becomespoorer, the stabilizing effect of the tuned circuit is reducedand drift of the oscillator may occur. On the other hand, ifthe broad peak is higher than the sharp peak, the oscillatoris overstabilized, the pull -in range becomes inadequate andthe broad peak can cause double triggering of the oscillatorwhen the hold control approaches the clockwise position.

Remove the oscilloscope upon completion of this adjust-ment.

Horizontal Drive Adjustment (for correct locking range).Turn the horizontal (frequency) control until the picture fallsout of sync with the diagonal lines sloping down to the right.Slowly turn the horizontal control counter -clockwise and notethe number of diagonal bars obtained just before the picturepulls into sync.

Pull -in should occur with one and one-half to three barspresent.

With the horizontal control set at the pull -in point, adjustthe horizontal drive trimmer CI71 counter -clockwise for abright vertical line in the center of the picture. Turn thetrimmer clockwise until the line just disappears.

Set the brightness control to maximum and adjust thewidth control so the picture fills the mask. Return the bright-ness control to normal and readjust the horizontal drivetrimmer as above.

The picture should pull into sync with one and one-halfto three bars present, remain in sync for approximately twofull turns counter -clockwise from pull -in, and fall out of syncwith between 2 and 5 bars present before interrupted oscil-lation (motorboating) occurs.

125


RCA Victor

TUNERI

UNIT 31 23 13 L2t

KRK- 30SI-E St -E

123 I REAR FRONT 13

LIB 2 12, 1.10 18

CIRCUIT SCHEMATIC DIAGRAM KCS88J, KCS88K, KCS88L, KCS88M or KCS88VA

16

J2I F

P302 INPUT

RIO1001( -

C 19 SI-231000 REAR

K 7

4 03.*5 9.

a -

TP I 4111

9*

C51470

C 230.68MMF

JI-F PI- mREAR PINVIEW VIEW

0260

I.10 \R2120

_ 3000 I moo

51

RI44 820

4\A.

-IC13 027 5270 Igg

REARSi C 0.0 7-451-C

126 ,FRONT

1.--r175 .2 7I)I 2.2 L33 EH H (-1000 /000 ......1

128124

. 3 1

L29123

.4 io. .

° C34IR571( IR2.11X39 0 ' 30 470

IL22 06 e-072 T V1

31

-) q050 CONTV2.TR2.

TP4'19 5I -87P- 2 136

V2IrT -11

L43

0S6C. )41CM8IXER C822°1 7

12833 E 6 300, >

C16 .'4+1450

L44 L4 " '15- -3 5

L

L45 L .3 1 +90v

-1'4476 L739

' . C21

4

7 .1, 0.0-3T_-,_. 148 1,'"3 117

L49 C 221 6210.8-3,. 120

ANT. MATCHING UNITLS L4 LI

F-14 I -F I- FI TRAP TRAP TROD

C25

51 A C27REAR FINE

I

.2 LS?,

*31.58f

15,:5

1.51155

SI-Aoo FRONT

O

1153

L52153

CI7 C18

C 241 R1210 I 100K

TP.3

--/C250.8- 3

CHANNEL SELECTOR SWITCH SIFRONT AND REAR SECTIONS VIEWEDFROM FRONT AND SHOWN INCHANNEL 1.10. 2 POSITION.

I- 11 HF SECTI ON -1-C300 /-/ 0,}{r/, OMITTED IN i

C303 C303 Z SOME UNITS I CR 301Ali 8I K3D OR

L303A = L3038 1311 11N 82le__,_.309 MIXER

®C3113 C-4307 0C3121 1 V301 C b.fl

_H1 A r 1E1 6AF4 T.-u

- - osc

R302680oC309

L 1000

123036800

R3012200

N N WHEN USING COMBINATION UHF- VHF ANT.CONNECT TRANSM. LINE To VHF TERMINALS.

FOR SEPARATE UHF AND VHF ANTENNAS.DISCONNECT mi 10 5 . AND CONNECT TRANsmLINES TO RESPECTIVE TERMINALS.

R5222K

UHF VHF

F41- ANTENNA*N.

it I TERM. BRO.

448551

517 SI

VHF UHF

C 305

T

I7C41 7

c3op / I 030 I

-79-3

I-304 -TB

+280 V.

c72, w104

R -FA-6 c

103

0260 V.

C 130.0022

7,041ST. PIK

I -F TRANS.

PC 101 ?

r;z:,°L.C101 TAKE OFF

3 TRANS

v N35

6CB6NS DIX I,

NIPL

V o,6AUG

SOUN DF AMPL

T noS2ND. FIX.

F TRANS43.0 MC.

c *0 .IV. A

R146 8117150 K 1000

C 1201 R118 c 119i7

0.471 33K 1470 =

S

01098

12AU 7A -G -CAmPL

0.5V

5[1/48151160K

ILI 4, ce,

.1-21300

0290V.

1'12350 5? C179

0.39. 280 V.

0131 30518K 6 X 8

1ST SYNC.C1410.1 +4631

2.2 3184

4,1

C140330

VII2

65N7 -6THOW. SWEEPOSC. B coNTR.

-21V I

RIBI EiE,3_,_330K HH

68R182 R1664_06462011 82 IQ 1-.022

8153

-4-100 K

J.50K-A-

(1660.47

R1853900

3 815391

RI5

ME

LI20140611FREE

Is 193 0

R18947 I(

C16- 7330

818600 K R190

I. 6.8MEG.

AP

The schematic is shown in the latest All capacitance values less than 1 incondition at the time of printing. MF and above 1 in MMF unless otherwise

All resistance value in ohms. K = 1000. noted.

250V.

126

R105

R106

clockwise rotation.


RCA Victor

T102RATIO OCTTRANS.4.5 MC

V 102

6A L5RATIO

DETECTOR

3.2

10KB C105 6 _LC108

leo 0.4710 K

DPI 1-2.9 V.

103cio60.IV

7

Ito.%004

)00RIO 4IC 10739K T033

Tv 101TEST

"' POINT5101

FRONT

FRONT AND REAR SECTIONSOF SWITCH 5101 VIEWED FROMFRONT WITH SWITCH SHAFTIN EXTREME CouNTER.CloCKENI5EPOSITION No. 1

P05.1 - TV. MIN. HIGHS2 - TV NORMAL3 - TV MIN. LOWS4 - PE1000. MIN HiGNs5 - P0000. NORMAL.6 - PHONO. MIN. LOWS.

* 5101REAR

610813I MEG.VOL.

CONTR

C 1 1 8C105 -1 1 F'.01 -1 1.1100

1 i (EgA3

4+10 MODELS 2155o,u 502U AND 518U KCS 8865311TTED- 5101,3101, W101, w102, C117 AND CHANNEL IND. LAMP.BANGED- cno9 TO .0047, C112 To .001.ONNEcTED-C1/39 To JUNCTION of 0104, RI54 AND C107

C112 BETWEEN 0103.7 AND &ND81.54,C11/3 AND V116 -I To GRD.V 116-10 To JUNCTION OF 0147,12197 AND IR 105.2

IN MODELS 218 523U(KCS 88VA) 000 Sls 537D (KCS 880)RANGED -CII3 To .0018 , 109 To .0027 AND C110 To .015

12

0100

6C 5 6 3RD P rt.

9Dm PL 45.5 MC.A.

+1240 20123 1360.3.201

812418

230V

2556

C

C182.001

LI19

V 107

6C B6360- PPL/R I -F

AM

K

2.2 V. Z

,125f$ 6127.001 180

5

7 1074TH RIX L103

TRANS CR 101 36 00.1.1MC_44.5 2ND DET ORNWHT

EP-Cr470

+280 v.

C

I

PC 102?

136V

1.001126

C133470

RI28470

?0128

110

R1293900

L 104250 MOH

GRN

42 V

v108 A

6X8Vi Of 0

AmPL.

9 380

R 130120

01290129.0039

C 110

00130 75rAti47 000.005

613?275

R 3212/5

1020

0132880 OF 'r'

V1036A V61ST AUDIO

AM PL.

_LC A113.0027

2 5

21 -S -501U to 21 -S -537U incl.

V 104

6AS5 T103AUDIO AUDIO

OUTPUT OUTPUT TR.

P.MSPEAKERS

240V BLU

1

o. 1 >t -, 'I

C117 g',r ,( I FAC52,48,LtryA

.0027 0'A'A

2. 8 'I SPKRS.114

C112 -L

1-.. 7 >-, \f* i

I L.,>_._-, A270 I1330)0 +I ,..,47 1 KCS 88 M

I C '+'.' 'g':c-'2:2ZZ,,R2,.,.._,>iii, qCOLOR00T

FOR CORRECT SPEAKERPHASING REFER TO COLORDOTS FOR PROPER CONNECTIONS.

1<05883,88K

1-5" 06 1-8'SPEAKER

8135 L106lc/ 250

MU

R1364700

R13415 K

VIIOA

R157 12AU733K SYNC. R162 C 145OUTPUT 22K .0033

+02 T0014233

64 -Lc NMI _LC14.6+7.9 V 2 10 K aj 220 10082

.021561:1. 390 K

C154 R158 y470 1200

RI613900

- C1700. I

081243

T

vii0 B12AU7VERT. SWEEP

OSC DISCH

RIGS 6 175 V8K

-GIV.

C.104369 ig-r"

R 1641.5 MEG

VERTICALHOLD

CONTR

1

C1470.1

+280V

RICO470K

8167 C152 0155 817222K .015 .022 22K

rC/115VO-Hh---4"1.0022 33'"'

S2'13_2,0-t(- 5

R173

0154470K

.068 R169 R174390K 2.5 MEG

VERT LINE

5 2CONTR

VIII

6K6-GTVERT SWEEP

OUTPUT

C1310.1

159

Z L 109

'64.5 MCTRAP

12AU7..00E0

OUTPUT

+280 V.

L IOU180 MU

wEcr C1350.1

+200V

6.80

R137470 4/1

R108010 K

PICTURECONTRASTCONTROL

C 134 B 014030 MD.141-

+820

T108vERT SWEEPOUTPUT TR.-

BL

C151 6168.056 18 K

R1653.5 MEG 0149

2 HEIGHT T .01CONTR.

RI7 I8200

#R120971(

LI 21H012

SINE WAVE

C168.01

RI92820 K

C169 R194470

R193I MEG

IR 19139 K

47

C17110-160NOR. DRIVECONTR.

tI02.0012

P101

v11.3

650.6-GT

0.3 AMP

E1OR SWEEPOUTPUT

158V.

C 1730.1

L'n

C174 RIBS0.27 / 100

RI9612K

05V T OTRANS.".'

I -

O

255VC156

,

1 8176 -1R

680 K175

B20 l<

0114

1B3-GTH -V REcT

+15,400V

_

1

RED

R 1423910

L 107mu.

SPNANT

01417500

0 V

+2800

R 177220K

R175200 K

BRIGHTNESS 2

CONTROL 3

R143470 K

0

10

R119ISO K

C157.022

5Ti

C1,5 -.047

C 176270

LIIIWIDTHCONTR.

V115

6A X4-GTDAMPER

.273L112 5

1.5 NUN

0177 C137120 330 DEFLECTION YOKE

-I F-.-161 - -1 RED

- I

C180 vERT. COILSI

1'191 L115 L114 N

R203Y IF. 1000

1g_ R201 R2021I=_ 560 560 I TEL

L _ _ BLK

pio2.PIN VIE

RED

15510.1

v116

21ZP4A2IZ P413KINESCOPE

J102F

REARO'ER

CHANNELNIJ

V 117

5U4 -GRECT. T1 I

- -1RED

1

1

RED..

I oI

GNN

GEN- TEL

.5V.30

V

L113

RN

6.30

S 102

BLK.REO

BLK

R204100 K

BLK- 8±1.J 5/03- INTERLOCK

+200vSUPPLY

-C132.4 C134.,180 Mr 11 00 Mr

115V 609SUPPLY

(See next page for chassis top view)

Direction of arrows at controls indicates All voltages measured with "Volt-Ohmyst- and with no signal input. Volt-ages should hold within 20% with 117v. a -c supply.

Schematic DiagramKCS881, KCS88K,KCS88L, KCS88M

or KCS88VA

127



TO ANTENNA

JI02YOKE

SOCKET

*J101PHONO INPUT

JACK

V1I41111/B0161VIV RECTJ

VIIS6AX4GTDAMPER

T2ANTENNA

TRANS.

F101FUSE

V1136BQ6GT

HOR.SWEEP

OUT.

V11751J4GRECT.

PCIO2OR

NOTECHASSIS DESIGNATIONS WITH *X"AS THE FINAL LETTER, USEPLATE ASSEMBLY INSTEAD OFPRINTED CIRCUIT

12 AU7

VIDEO OUT.111 AG C

TUNER UNITKRK 22 D

68Q7RF AMP.

7104IV FIXI -F TRANS 12 AU7

21-S-501 to 21-S-537 incl.21 -S -501U to 21 -S -537U incl.

6xaOSC &MIXER

sioi a 5102/R108A aLOCATED AS SHOWNFOR MODELS 21-S-523,AND 2I -S -523U

VIII6K6GT

VERT.SWEEP

OUT.

TIOBVERTOUT

TRANS.

V11265N7GTORIZ.ODE. BCONTROL)

V104SASSAUDIOOUT.

FINETUNING

*OMITTED ON MODELS2I -S- 518 (U)21-S-501 (U)21-S-502 (U)

CHANNELSELECTOR

SIOi *TV -PHONOTONECONTROL

RI 6 4VERTICAL

HOLDCONTROL

111 \R174a

VERT. LIN.ADJUSTMENT

R178BRIGHTNESSCONTROL

RI65HEIGHT

ADJUSTMENT

C 171 KjHORIZ. DRIVE /,ADJUSTMENT

LI 21HOR. SINE

WAVE COIL

V1036AVG

151 AUDIOAMP

L1094.5 MCTRAP

0

CRASS TOP VIEW

VIOB6%6

Chassis Top View (shown with KRK22D Tuner)

128

L I20HORIZONTAL

(F REG))CONTROL

01 t- PH11:1;)

T11NESWITCH

RI 084PICTURECONTROL

S102 a R10813ON -OFFSWITCH SVOLUMECONTROL

/11

SPEAKER LEADSLOCATED HERE ON

MODELS 21- S - 523 (U) ONLY


RAYTHEON MANUFACTURING COMPANY

17T18 and 21T19 CHASSIS(See list of models on next page, over.)

12 BH7v. osc. a\OUTPUT \

* NOTE:V- IO. V-I2,V- 13FILAMENTS IN

SERIES

6CB62ND IF AMP

6CB61ST IF AMP

FUSIBLERESISTOR

*25AX4,DAMPER

SELENIUM IRECTIFIERS

L

6AN83RD IF AMP

f/TECTOR

6AN8VIDEO AM1:1

SYNC SEP

* 25BK5AUDIO OUTPUT

I 2AU7AFC a H.

OSCILLATORCOARSEH. HOLD /

H. HOLD W J 6AN8COIL 0 xv SYNC AMP

AUDIO IF AMP

-x-25BQ6H. PULSE AMP

6 BN6AUDIO DET aAMPLI FIER

()BUZZCONTROL

elI X2B

H. V. RECT ij

R. F TESTPOINT

C6

Top Chassis View

L 200

L202A (TOP) T200L202B (BOTTOM)

O

L100BUZZ

CONTROL

T201

T100

(Continued on next 3 pages.)129

MOST -OFTEN -NEEDED 195S TELEVISION SERVICING INFORMATIONRAYTHEON

MODEL CHASSIS

M -1750AM -1750CM -1750GM -1750KM -1751DM -1751FM -1752EM -1752LM -2160AM -2160CM -2160GM -2160KM -2161DM -2161FM -2162EM -2162L

17718177181771817T18177181771817718177182171921719217192171921719217192171921719

ON -OFF VOLUME

I -L HOLD BRIGHTNESS

FINE TUNING

STATION SELECTOR

Top Controls

FINETUNING

OSC. ADJUSTMENT

V SIZE V LIN

17T18, 21T19 TELEVISION SCHEMATIC DIAGRAM

L II C18R8 120

V. HOLD

ICTURE

C7

IT

STATIONSELECTOR

Service Controls

R44700

C5I tO

LIO

ISK

6J6CONY- OSC

R 710K-9-3A/0-41

R6

R.F TESTPOINT

0-0- 0 0 0,0 !L3 L4

60 5

R32200

1G 300

T225000V

IGIO10

If F-4FINETUNING

G85

4 2

100001 1050

110.1.7.

Nor

RI5

R 115K

7

R 300 VERT VERT10 K

5000500VR3022 2M

- -T-- A 52)73 1

220K I

iill///ANTENNA LTERMINALS

C500470

220K

R502

133 L C50215W 5241 8 V-13

500V 25AX47

{,0SAFETY

INTER. LOCK

0503 2 V -I25000 25806

ON -OFF SWITCHON VOLUME CONTROL

C16BOO

BLACK

C14800

WHITE

NOTE:CAPACITOR VALUES INUNLESS OTHERWISE MARKED.

RESISTOR WATTAGE SHOWN IN1/2 WATT UNLESS OTHERWISE MARKED.

25V

.7V

8200 R20212 K 47

02001000500V

C$0930

V-3

6CB61ST IF AMP

155V

V-74

6AN8AUDIO IF AMP

-.4

L200C2Q3

"47

6vC143E- 5 O. 2N0 IF AM

a

62V0101470

658

RI 0133K1W

C10010K

500V

R203 204000

G5

5005

..C102013 -04:12g°

R205000=

li-I=' x 500V -

L201_Jo -06-

.2.2 UH1.6.1.

-A- -1- -r20V Y 68V 68VP -P P -I: P -P

VE HORIZ /

R303 R304 R30522K IM 560K

125V R506

SELENIUMRECTIFIERS

FUSIBLERESISTOR

C504 C505

v-io11MF 115005MF

v 9

2 5BK5 R503 14.54220K

830647KIW

T500

2000

820662

65V 7PP /

TP -P50V

MF200V

IV

C4002000

500V 1410-22V

_+255V +245V +170V +130V

SOURCE SOURCE SOURCE SVOICE1-1

n A A 41

R504-sevv -

R505 215'2700

'2500 P -P13W 5W

BERT

50 to 108V

V -B

12 BH7

C403.1MF200V

*E. ;791:7-.'CIO2OMF 10 MF + 0601

o FILAMENT 0

7.-

SOURCE -T.- 30 -AT -TI0600220

82

50 V ..C-11

C 50005 6

v. osc aOUTPUT

R403LOOK

V HOLD

130

R4046000

V. LIN.


VOLTAGE READINGS TAKEN WITH A V.T.V.M., LINE VOLTAGEAT 115 V. AC AND THE ANTENNA SHORTED TO CHASSIS.

Raytheon Chassis 17T18 and 21T19NOTE COIL RESISTANCE READINGS NEAR COILS AND TRANSFORMERS WERE TAKEN WITH

AN OHMMETER DIRECTLY ACROSS COIL BEING MEASURED EXCEPT THOSE INDICATEDT100 L100

R103 CI6 BY AN ASTERISK (), ONE LEAD WAS DISCONNECTED. COILS SHOWN1

WITHOUT A READING HAVE A RESISTANCE OF LESS THAN ONE OHM.

.8"t 245V

R102750

BUZZ

L 202

0 to 6.5V

= C210 1

II5V

L202A

R215510

1000C207 (.208 L203680 T!,00. 35 229500V 1500V 2.8A.

V 5A

1/2 6AN83RD IF AMP

C213

15000500V

7200_ _

R2168IM

VOLUME I

-4

R106 L

330K

V- 5 B

1/26AN8DETECTOR 8 AGC

OV

VS

235V T101 PMSPEAKER

vB25K5 480AUDIO OUTPUT

R108ISOIW

L2092 2UH5.4n.

47

0108.OIMF600V

-0-

R216A1000PICTURE

4706 -Lr.

C222

T201

L.207305UH8.4n_

R2I856002W

I-208270 1.197.7n

CABINET

C22I1

1

33

7P- PI

VERT

C404MF 1-

400V

R24.g,54

R4H' 2,7p iOOK

-50,

75VP -P

R407R408

3MV. SIZE

IC4051000

500V

_ERc225Z450V

R41047K

VERT

BLUE T400

770n.

RED

WAVE FORMS WERE TAKEN WITH A TRANSMITTED SIGNAL AND PICTURE IN SYNC AT ALL TIMES.THE WAVE FORMS AND PEAK TO PEAK VOLTAGE READINGS MAY VARY WITH STRENGTH OF SIGNAL,PICTURE INFORMATION BEING TRANSMITTED, AND ADJUSTMENT OF VARIOUS CONTROLS. VS DENOTESPEAK TO PEAK VOLTAGE READINGS WILL VARY WITH SIGNAL.

R40933005W

BOOST490V

R22

6

REEN

226.IMF400V

10 0R220 TOOK 2_6,L210500K

BRIGHTNESS ±

C225

R222

1000

010246V

OV

68n.VERT.a/V.W

R229 R225560 560

,SLQA.11_,

495V

C227 R223__J .022M FT 22K NOTE:

1 * I

200V _i_ NOT INCLUDED5V 5V-. T IN ALL SETS

P- P1 _Y_

Honi2

DO

01

OK

602

.047MF200V IOVR6 3

82K R6053900

R60650K

H. HOLD R6I6

V -I I

R6I5 36100K . 04705 MF I2AU7

AFT B HOR.OSG

41 I7V

4) 2C603

MFIV- .022

- 200V

I85V

33K

L601 R60847K

1- 35 to190V

OL600

STABILIZER

74n.

R604 C604150K T .47MF

4. 200VR607

4 0068 600V

06071

330

62rt

022MF400V

T202

C22847

2 KV

1-4 I

5.9.n.

HORIZ

0230

473KV

//TI(///e. P°P

BOST15 MF C614200V

< C6I3220

HORIZ

NIkz260

R6I0 O. ....R609 100 49 082000609

.001 MF600V

R61470K

21NOTE:

610047M

-400V

150K MAY VARY/24V FROM 75010 910

P -P

V- I 2

258Q6H. PULSE AMP

130V

R6I282002W

245V

A4DAMPER

'a- <

L6028 UHIliI.

225n

010.5

4.6n

62AC611.IMF 490V

11Mi. BOOST

SOURCE400V

V-1517HP4

Or

2IYP4PICTURE TUBE

T600

R6I31,5

V-14

IX2BH. V. RECT

NOTE: Capacitor C608 should be 470 mmf and a 80-480mmf trimmer is connected in parallel with C608.

131

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONRaytheon Manufacturing Company Chassis 17T18 and 21T19 (continued)

PRE -ALIGNMENT PRECAUTIONS1. If sweep generator does not have a balanced output,

connect a 150 ohm resistor in series with the groundlead and 150 ohms minus the internal resistance ofthe generator in series with the hot lead.

2. Connect a 1000 mmf capacitor across scope term-inals and a 10K ohm resistor in series with hot lead

as close to test point as possible.

3. Connect signal generator through a 1000 mmfcapacitor.

4. When aligning the IF Amplifier be sure tuner is setto channel 10.

VIDEO IF ALIGNMENT

StepNo.

1

SignalGeneratorFreq. (mc.)

SweepGeneratorFreq (mc.)

SignalInputPoint

OutputPoint

Remarks Adjust Response

23.926.3 25

Pin 8of V -5A

Scope at IFdefectoroutput

Connect shortbetween pin

5 and 6 of V-4

T200 pri. (top)T200 sec. (bot.)

Coupling rod

2Markers should fall 10% down. If response curve is not as shown, readjust coupling rod (bottom T200)for proper bandwidth and T200 primary and secondary for flat response and maximum gain.

3 21.3Converter

grid

VTVM atPin 8

of V -6A

Remove short.Adjust generator

for output of approx.2 volts DC on VTVM

L202B(bottom core)

Maximumreading

4 26.5 Convertergrid

VTVM atPin 8

of V -6A

Adjust generatorfor output of approx.2 volts DC on VTVM

L202A(top core)

Maximumreading

5 21.3 Convertergrid

VTVM atPin 8

of V -6A


L202B(bottom core)

Maximumreading

24.0 Convertergrid

VTVM atPin 8

of V -6A


L200 Maximumreading

25.0Converter

grid

VTVM atPinfor8

of V -6A

Adjust generatoroutputofapprox.

2 volts DC on VTVMLl 1 Maximum

reading

8 25 Convertergrid

Scope atPin 8

of V -6ALl 1 Rock for flat

response

923.8

26.6525 Converter

grid

Scope atPin 8

of V -6A

Markers should be50% down and re-sponse curve shouldbe as shown. If not,repeat alignment

Checkpointonly

4$6

Picture IF frequency 26.75 MC - Sound IF frequency 22.25MC.NOTE: A very short lead from the generator must be used to prevent regeneration.

SOUND IF ALIGNMENTSound Alignment can be performed without test equip-ment and without removing the picture tube from thechassis.

1. Tune in a TV station and adjust fine tuning untilsound bars just appear.

2. Turn T201 primary (furthest from chassis pan) slugall the way out (counter -clockwise).

3. Turn same T201 slug in (clockwise) until the horizon-tal scanning lines are smooth and continuous.

4. Readjust fine tuning for best picture with adequatesound.

5. Reduce signal strength at antenna terminals byof an attenuator or similar device until a "hiss"companies the sound.

6. Adjust sound pick -off transformer (T201 secondary),interstage transformer (7100), quadrature coil (L-100) and buzz control (R102) for maximum clearsound and minimum buzz.

7. If "hiss" disappears during step 3, further reducesignal strength.

useac -

132


StivrA&AteSears, Roebuck & Co. Chassis 528.271,

528.292, 528.300, and 528.303

Chassis271, -1, -2,1271-3, -4

528. -292, -1,

1 292-2, -3Television Receiver Cabinet

Description

Chassis300, -1,300-2, -3

528.-1 303, -11

Catalog Number Catalog NumberConsole, Mahogany with Doors 4150EConsole, Maple with Doors 4155EConsole, Limed Ook with Doors 4153E

4125 4133 Console, Mahogany, Open Face 4140E4135 Console, Limed Oak, Open Face4127C Console, Maroon Leatherette 4127D4129A Console, Marlite Mahogany 4129B4135B Console, Masonite, Limed Oak

4108A 4118B Table Model, Mahogany 4118CTable Model, Limed Oak 4119ATable Model, Maroon Leath. 4113B

4113A Table Model, Red Leath.3104A Table Model, Black Leath. 41123102X 3112X Table Model, Brown Leath.4108 Table Model, Marlite Mahog.

Table Model, Masonite Mahog. 5113

Circuit diagram on the next two pages alignment on the page following the circuit.

All chassis except 528.271, 271-1, 271-2, glass picture tube. Chassis528.271, 271-1, 271-2, 271-3 and 271-4 contain a 17BP4, 17" glass tube, while chassis 528.303 and 303-1 contain a 21WP4, 205/8" glasspicture tube.

CHANNELSELECTOR

FINE TUNING-

CRYSTAL

HORIZ. HOLD

\ HE IGHTVERT. HOLDVERT.

LINEARITY 11 /

ll

9L 204

11.7

TOP

T3TOP 6 BOTTOM

TI

TOP 5BOTTOM

14TOP 5 BOTTOM

TSTOP 4 BOTTOM

LITOP

T6BOTTOM -

a

00

BRIGHTNESS

edam.

0 o

4D

LS -BOTTOM

HORIZ. OSC.(L9)

VI9

`TE

41)

VOLUMEON -OFF CONTROL

LI3

T9

TIO

' 1_1

PICTURETUBE

\- WIDTH

NORIZ. (L 10)LINEARITY

(LI2)

FUSE

CONTRAST

VI, BAU6- SOUND I.F.

V2,678- RATIO DET. B IBT AUDIO

V3,6W6- AUDIO OUTPUT

V4,60815-157 I.F.

VS, 6C86- 2ND I.F.

V6, 6C86- 3RD I.F.

V7,6C86 4TH 1.F

V111,6CL6- VIDEO AMP.

V9, 12AU7- SYNC. SE PE RATOR

V10,6C4- VERT. OSC.

VII, GAM- VERT. OUTPUT

V12,6AU6-A.G.C.

VI3, GALS- PHASE DETECTOR

V14,6SN7/07- HOR II. OSC.

V16,6806 - HORIZ. OUTPUT

VI6,183/07- HIGH VOLT. RECTIFIER

V17,6AX4 DIODE DAMPER

V18, SU40 - LOW VOLT. RECTIFIER

VI9, PICTURE TUBE

V20,674 OR 6AF4 - UHF. OSC.

V21, 6U8 - VHF. OSC. 8 MIXERV22, 68Z7, R.F. AMP

Fig. 2. Top View Alt chassis except 528.300, 300-1, 300-2 and 300-3

133

1-WerAAVA'Afil.00: .0061-1

L---- --J


Sears, Roebuck & Co. Chassis 528.271, 528.292, 528.300, 528.303

lAys.,wrei. Lap

A.2011770./ 4 5,11.{.

/Hi see 7ai-

171 Sri -EP

To MAIIr1,1P

44004,0 Covweno

Fig. 7. Test Equipment

50t

50%

r -

Connections

4725 715 452 44.1 42.9 4255 41.25ADJ. SOUND TRAP VICO) T41801) L2ORTOP) T5111011 5010101

T41701,1 I.f TG(80T) LZ (10T) 7518011 73(T0P)

Fig. 6 41 Mc I.F. Response

STANDARD COIL62 CHANNEL

ALL PURPOSE TUNER

2800

1

1

F

-.8 C7Sr617 120

IMF

IK

18

-112 T6

11

VI6AU6 235KROUND 1.F.

LIU.S 1110SOUND

TAXI -Off

SA C220IOW

R1540

rU I

125

C4

180T

R210K10.

745 MC

RATIO OCT TRANS

P3220

11

C

V46CB61ST I.F. 1109.

2.9MC.BOTTOM

73Iv L F r 41.2511C.

I x=21 TOP

6CB6240 IF

2 4

R23 1300

4.7R

624IX

62547

2110 LF

45.2 MC.BOTTOM

C22I C23col

.001

NASPs.

R26100

I RESISTANCE ARE SHOWN IN OHMS 01000, mEG1,000,C0C

2. CAPACITANCE VALUES ARE STD UNLESS OTHERWISE NOTED

3 RESISTANCE 1ALUES SHOWN ARE WITH PART DISCONNECTECFORM CIRCUIT ALL 5E54510143 I42 WATT UNLESS OTHER-WISE NOTED.

vcLrAGES READ WITH ELECTRONIC VOLTMETER, ANTENNATERMINALS SHORTED, TUNER ON UNUSED CHANNEL.CONTRAST AND IIRILLiANCE AT MINIMUM. -4.5 VOLTS 41143ON VIC LINE AT C-24 OTHER CONTROLS AT NORMAL,LINE VOLTAGE HT VOLTS

S. ALL WAVE FORMS MEASURED IV TN STRONG SIGNAL INPUTAND WITH CONTRAST SET TO GIVE NORMAL PICTURE.GC. LINE OPERATING NORMALLY.

VERTICAI. 12171491117011 011111804K.(T17-1091

I. UPC 8.210 11.20 LEGEND FOR COILSWOUND ON RESISTORS.

P. P307.

V185U4

LOW VOLT. RECTIFIER

YELLOW

T11TEL. 54 3441E

RED

423

RID -

AMP

11.3SRN

4.3

L13FILTERSMOKE

rrn85" COLD

I SA ME

di 1.111.

C3I-40

390V,

000010 AMP

742IS

150.mmr.

V9I2AU7

STMC. SEP

R3270)1

3O

-LIKAA,MAALL--s- _

L

R493.011

ioy

.757524

MPG CON40

BO 44

V.

IS V.P -P71150

VI3GALS

PRASE DETECTOR

IV.

rt

C830-1 /773 .01

GN

C33- 001

TV.

11741000

C34_.001

6764.7MEG.

120P.P

75710

R503.30

C54.0047

7747011

VI46SN7

60012 osc

134


V2818

06710 OFT I Ill AUDIO

R6li

'IV

50V

5

P140610

0-46SI

12.70R27

C:t.iRS

gZ1;500K

.12VOLUMECONTROL

R74MEC

CTS005

Sears, Roebuck & Co. Chassis 528,271, 528.292, 528.300, 528.303

55T.

R9X 2700

Re

1.6 MEG

V36W6

AUDIO OUTPUT240V I CUE

TLOUTPUT

TRANS

II

R1S220..24,

- :745 MC

1V6

6C8631401.P

tl

R2S150

5

TO540 I. F42.9 MC.SOT 709

130

130

C26

C25

.001

V76C86

41141 F 1300

Lieop'

T6ITN LE45.2BOTTOM

R94100

69

.0016

1064

1

701C71 1 C72I4.4 IMF 3

SJ

L3149 UNRED I VINT

V86C L6

VIDEO AMP

L7 1duimi.C>

R324.7K

SPEILICIR3.2

BLACK

L 4.5 MC TRAP15001412.oau(

(00

L8

C26100 47616111

to-6

350

R36105

VR343005,

CO ------

Ian

L6

--20-550 (OUT 100 AMPLITITUM OF VS )

1.,0-.I, MID AT 61401191061 carntw.

VI9

P11. TIME

I

265 UNILK S eRn

14113190.75 1001(OR. SRI

R392.2029.

2000P

30.1140P -P(71( 30,5u

(, I Wnr3041

V106C4 VII

T7 .571000 VEST 05C. 6AH4VERT, VEST OuTPuT

BLOCKING70605

/47 1100" 0 67EL. GREEN

C40RS 0 D '

2 3 ' ROSCole R57

'..545, Scut 21005, I ' 3.1 $00 R5I1

,C047ME0

C36 MOO

T 2.2I'3 VERT 156

C37 i-"-- 00100T

. MOLD4 'I hitil. .TC7,C:

r1216120 STOP

220

5647 7

- -.

- v - --P-

5Vp155V.

7 V_ Ta._711175.

L91401111 09c

R791.55

1113IC

CSI -0U

5'30 3.

R61300

TIvERT

OUTPUTTRAMS

700.9.

C52-0

00TR60,.

2.50vEICE LIN. 40

0.51-q Pen oR59 3504 M.470 I 4

I C42500.

ORM IL

IC45111113

4705 I 47OK

10

540 V.

1 C74.o47

V PP797561

1,77, - 646C3oos V12

6AU6 06

LevERT YOKE

C41

1.047

TOIL

164540

*65560

R11260K

514

C

CO.330NM,

ass1.20

50KPP

rani._

660VII

001512 OUTPUT

Rae100

1409

IS.IOU".

Re9150Sr

61

11'II

11%.

1101,11

11

11C 1990

IIIA 29IK

II ia'II

0COI

LIO11 STARTII c11 d

FINISMe

II G 1

5-30v,P -P

T10N01112. OUTPUT

TRANS R91

2153 4

00I

1 V

1095

R70100

R68leo

z R97

R69 C47120K

ID047183HIGH v01.7

RECTIFIER

C62-- 55 55F

IIAMCorp

LI190910. 7005

5n

C63

5157.

047

53\V--4(°' Ic4t5V16

C6S047

R11121111

rMF2 0v

VIT6614DAMPER

Lit1 00012

PO"

7

R98loo it

135


Sears, Roebuck & Co. Chassis 528.271, 528.292, 528.300, 528.303, continued.

TELEVISION ALIGNMENT PROCEDUREPRELIMINARYAlignment is an exacting procedure and should be undertaken only when necessary. The following equipment is required for alignment work.

1. Signal generator, with an output of at least 1 volt maximum. Crystal controlled or calibrated markers for the sound (41.25 Mc)and picture (45.75 Mc) IF carriers are required in addition to the following variable frequencies.

4.5 Mc Intercarrier Sound IF41.25 Mc Sound IF Trap (T-3, top)42.9 Mt 1st & 3rd I.F. (T-3, bottom; T-5 bottom)44.1 Mc Converter and I.F. input (L-2 bottom; L204 Top)45.2 Mc 2nd & 4th I.F. (T-4 bottom; T-6 bottom)47.25 Mc Adjacent Sound Trap (T-4 Top)

2. Electronic voltmeter (VTVM)

3. R.F. sweep generator with a frequency range of 40 to 220 Mc with a sweep width of at least 10 Mc, having an adjustable output ofat least 0.1 volts.

4. Cathode ray oscilloscope, preferably with a wide band vertical amplifier and an input calibrating source.

VIDEO IF ALIGNMENT

StepSignal Generator Output

Indicator C t to Adjust Remarks

Apply -4.5 volt bias to AGCline, - side to C-42, + side tochassis. Short antenna terminals,set channel selector to unusedchannel free of harmonics orother interference. Adjust signalgenerator to give reading of ap-proximately 2.5 volts on VTVM.On all "maximum" adjustmentsreduce generator output so thatVTVM reading does not exceed2.5 volts. On minimum adjust -ments increase generator outputto provide definite dip on meter.

Fr Connect to

1 42.9 McFloatingshield on

mixertube. V-21

VTVM Junction ofR32 and L7

T3 Bottom formaximum reading

2 42.9 Mc Same Same Same T5 Bottom formaximum reading



5 41.25 Mc Same Same Same T3 Top forminimum reading

6 47.25 Mc Same Same Same T4 Top forminimum reading



9 44.1 Mc Same Same Same L2 Bottom formaximum reading

10 44.1 Mc Same Same Same L204 Top formaximum reading

11

Sweep 44 Mc,10 Mc Sweep,

Marker tofreqs. inFig. 6

SeeFig. 7

Oscil-loscope

Vertical terminalsto junction ofR32 and 17.Horizontalterminals tosweep Gen.

T6 for 45.75 Mc50% position. L2for correct tilt.See Fig. 4 for

correct wave form

When sweeping overall pattern donot exceed 2 volts P -P (or approx-imately .3 volts D.C. at detector loadresistor) to avoid overload anddistortion of response curve.

SOUND ALIGNMENT

StepSignal Generator Output

Indicator Connect to Adjust RemarksFrequency Connect to

1 4.5 McJunction

of1232 and L7

VTVM See Note 1LI Bottom far

maximum reading,TI Bottom for

maximum reading

Signal generator output below .1volts, VTVM on low range (0-3volts).

2 4.5 Mc Same Same Junction ofR4 and C7

T1 Top for zero(mid -scale)

3 4.5 Mc Junction ofC29 and R40

Same See Note I L5 forminimum reading

This adjusts the 4.5 Mc soundtrap. For field adjustment seeNote 2.

NOTE 1. Connect two 100K ohm matched resistors in series between Pin 2 of V2 (6T8) and ground. Connect negative lead of VTVM tothe junction of the two resistors and the positive lead to junction of R4 and C7.

NOTE 2. As a field adjustment, the 4.5 Mc trap (L5) may be set on a signal by adjusting L5 for a minimum amount of graininess in thepicture. This interference can be described as a moving, shadowy, bead -like appearance in the picture which is caused by a break-up at extremely close intervals of the horizontal lines. This is most easily seen in the neutral grey shades in the raster.

136

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONMODELS

SentinelSENTINEL RADIO CORPORATION

(Material below and continued on the next five pages)

1U-701 1U-7551U-711 1U-7581U-714 1U-7621U-721 1U-7651U-724 1U-7681U-752 1U-791

WHEN REPLACING PICTURE TUBE ALWAYS HAVE FACE OF TUBE TIGHT AGAINST RUBBER STOPS

ADJUSTMENT PROCEDURE FOR DEFLECTION YOKE, ION TRAP, HORIZONTAL ANDVERTICAL CENTERING, CORNER SHADOW, AND PICTURE TUBE ALIGNMENT.

SOME 21" MODELS USE ELECTRO-MAGNETIC FO-CUS PICTURE TUBES. ADJUST FOCUS BY TURNINGFOCUS STEM FOR BEST DEFINITION.

CORNER SHADOW, VERTICALAND HORIZONTAL CENTER INGAdjust the Centering Tab, part of the focusmagnet assembly, so that pattern is cen-tered both Horizontally and Vertically.Additional centering can be obtained byloosening the 2 wing nuts and moving thecomplete focus magnet assembly.

Always re -adjust the ion trapif focus magnet assembly hasbeen moved.

VERTICAL ANDHORIZONTAL CENTERING

Adjust the two centering rings located on the beck ofthe Deflection Yoke assembly so that pattern is centeredboth horizontally and vertically.

ELIMINATING SEMI -CIRCULARCORNER SHADOW OFPATTERN OR PICTURE

Use same procedure as listed above on horizontal andvertical centering.

Caution: DO NOT USE ION TRAP TO ELIMINATECORNER SHADOW OF PATTERN IF BY SO DOINGTHE INTENSITY OF RASTER IS DECREASED.

REPOSITIONING LOOSEOR REPLACED PICTURE TUBE.

This rubber gasket around edge of Deflection Yokemounting bracket supports the picture tube. Itshould always be pressing very firmly against thebell of the tube, otherwise the picture tube maymove and cause corner shadow or shifting ofpattern on screen.To position loosen the Deflection Yokemounting screw "A" and 2 wing nuts "B"and the 4 screws "C". Push the completeBracket Assembly forward so that the rub -

aet fits snugly around bell of picturee. Tighten the 4 screws "C" firmly. IF

the foregoing procedures have been fol-lowed correct'y the picture tube should nowbe held firmly in place. Gently push thedeflection yoke forward and tighten the 2wing nuts "B". Before tightening screw "A"make sure that pattern is not tilted.

STRAIGHTENINGTILTED PATTERN

If Pattern is tilted on screen, ad-just Deflection Yoke position by-I. yoke -locking screw (A).

2. Straighten pattern on screenby sliding locking screw toright or left.

3. Lock yoke in proper positionby firmly tightening screw.

ION TRAP ASSEMBLYMaximum brightness will be determined by the position of theION TRAP ASSEMBLY:

I. Advance BRIGHTNESS CONTROL on front of chassis tomaximum brightness position.

2. Adjust the ION TRAP ASSEMBLY for maximum brightnessby sliding back and forth and rotating to right or left.Reduce BRIGHTNESS with BRIGHTNESS CONTROL andrepeat adjustment of ION TRAP for best positioning.

Caution: IF A SEMI -CIRCULAR SHADOW AROUND CORNEROF PICTURE OR PATTERN IS OBTAINED, DO NOT ELIMINATEWITH ION TRAP, IF BY SO DOING THE INTENSITY OF THEPATTERN IS DECREASED.

137

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONSentinel Models 1U-701, 1U-711, etc. (Continued)

RATIO DETECTOR AND SOUND I -F ALIGNMENT

In most cases only the secondary of the ratio detector coilwill require adjustment. This can be done simply by ad-justing the top adjustment screw of the ratio detector forminimum buzzbuzz with the sound carrier of a TV station. Forcomplete alignment use steps 1, 2, and 3 in the alignmenttable.

VHF ALIGNMENT TABLE

RATIO DETECTOR AND SOUND

PICTURE SOUND

90%

FIG. 4

ALIGNMENT

StepNo.

C t SignalGenerator to

Sig. Gen.Freq. Connect Voltmeter to Miscell s Instructions Adjust

1 In series with .001 Mfd.Cond. to junction ofL -I5 and L-16. See fig.

6

4.5 MC. In series with 47,000 ohm res. acrossC-66 a 10 Mfd. cond. See fig. 6

Maintain reading on 10 volt scalecontrast at maximum.

Remove 3rd video IF tube 6CB6.

T -I5 (top) and T-16 (bottom) for

max. reading.See fig. 5 & 6

2 In series with .001 Mfd.Cord. to junction ofL -I5 and L -I6. See fig.

6

4.5 MC. In sories with 47,000 ohm res. fojunction of R-60 and C-69

See fig. 6

Maintain reading on 10 volt scalecontrast at maximum.


T -I6 (top) forzero reading.

See fig. 5

3 In series with .001 Mfd.Cond. to cathode ofpicture tube yellow

lead. See fig. 6

4.5 MC. In series with 47,000 ohm res. acrossC-66 a 10 Mfd. cond. See fig. 6

Maintain reading onlow volt scale,


T -I4 (top) forminimum reading.

See fig. 5

NOTE I: For minimum buzz always adjust T- 6 (top) with the sound carrier of a TV station.NOTE 2: Alternate 4.5 MC. trap alignment: Adjust T-14 (top) for minimum 4.5 MC. beat on picture with a strong station signal.

PICTURE I -F ALIGNMENT

StepNo.

Connect SignalGenerator to

Sig. Gen.Freq.

Connect Voltmeter to Miscell s Instructions Adjust

4 Ungrounded convertertube (6U8) shield

44.0 MC. In series with 47,000 ohm res. tojunction of R-46 and L-16. See fig. 6

Tuner on channel 3, 3 volts biasacross C-49 positive side toground. Locality switch in strong

position. See fig. 6

T -I3 (top) formaximum reading.

See fig. 5


43.2 MC. In series with 47,000 ohm res. tojunction of R-46 and L -I6. See fig. 6




See fig. 5





Repeat Steps 5 & 6

T -I2 (bottom) forminimum reading.

See fig. 6



In series with 47,000 ohm res. tojunction of R-46 and L-16. See fig. 6



T -I I (top) formaximum reading.

See fig. 5

T -I I (bottom) forminimum reading.

See fig. 6


47.25 MC. Tuner on channel 3, 3 volts biasacross C-49 positive side toground. Locality switch in strong

position. See fig. 6Repeat Steps 7 & 8


44.5 MC.

45.75 MC.

response curveseries with 47,000

In series with 47,000 ohm res. tojunction of R-46 and L -I6. See fig. 6


position. See fig. 6NOTE: Detune T -I0 by turning

slug out as far as possible.

T -I (top) formaximum reading.

See fig. 5


In series with 47,000 ohm res. tojunction of R-46 and L-16. See fig. 6

(see fig. 3) connect signal and sweepohm resistor to junction of R-46

Tuner on channel 3, 3 volts biasacross C-49 positive side to



See fig. 5

NOTE 3: For visual check of IFConnect oscilloscope in

generator to ungrounded converter tube shield (6.16).and L -I6.

138


r

T

1U-711, 1U-714, 1U-721, 1U-724, 1U-752, etc. (Continued)vie

6BZ7FIE AMP.

I.F

Sentinel Models 1U-701,

ANTSTRIP

OSC STRIP

'COUPLING

'47`7,;',.-

V17

6U8OSC-MIXER

I00,0004, MIXER

7

I F OUTPUT470 MN I PLUG I, VIDEO I. F.

4'T -.1-400000 "A

1000 mrAF

A I -0' 07 oFMF

Cli000

L--

TC-I9

-

65-90V.

- TO-v

L

61.1)3OSC. MITER

120V

205

6BZ7R F AMP

Ov

LOCALITY ADJUSTER SWITCH IN STRONGSIGNAL POSITION.CONTRAST CONTROL AT MINIMUM.ALL READINGS UNLESS SPECIFIED MEASUREDWITH NO SIGNAL INPUTHIGH VOLTAGE READING TO BE TAKEN ONLYAT SECOND ANODE OF PICTURE TUBE.

ALL VOL-AGE READINGS MADE WITH AVACUUM YuBE VOLTMETER, WITH REFERENCE TO GROUND.

AG VOLTAGESU 520 VOLTS DC ABOVE GROUND

VOLTAGE VARIES WITH SETTING OF CONTROLS

6CB61ST vIDEC I F

6.3*

25

125

I 360

1B3GTH.v. RECTIFIER

DO NOT MEASURE VOLTAGESON THIS TUBE

6CB6

6AL5RATIO Del

6W6GTAUDIO OUTPUT

6CU 6OR

6B06GTHORa OUTPUT

NC

NC

NC

NC i40

550 NC

-28

NC

6CB6

25

025

4, 225

6AU6.smc SOUND

95

95

255 265

6SN7GTAUDIO AMP

HORiZ A F C. CONTROLU.S -1.8

158

6W4GTHORIZ. DAMPER

O

2.5

6CL6VIDEO AMP

225.,

240

12BH7HART OSC 8 OUTPUT

e, 125 6.3*

c, .00

520

-28

0

65 N 7GTSYNC SEP 8

W.p,HSE SPLITTER

6SN7GTHoFta 05C

5U 4GRECTIFIER

285

a;an

a.

a)

0

0;-4

.r4U

,-1ctl

0

c)

a)

0

13C.

139


74 6C136 = 6636 663B6 6641_6vi V2

VIn. VIDEO I.F. 211o. V DEO LF. f Sno. VIDEO I.F. VIDEO AMP.

0.;$. 110

r to

"

-a0oQ)

o.co w

a.

BC

70.,R-66

NOTES

0

L_ 2 ,

3

3 5SEE NOTE

Ar CHORE2-9

00000 4--

C-46 DEPTH CONY

15006, 270V 270VR-67

V9

6SN7GTSYNC SEP. a

PHASE SPLITTER

115v

1 SOME. MODELS 00 NOT HAVE HI-LITE AND TONE CONTROL.HI-LITE AND TONE CONTROL CIRCUITS ENCLOSED STDOTTED LINES IS OMITTED. AND C-72 BECOMES.01 MF 4000

2. PIN 6 Of PICTURE TUBE SHOWN NT DOTTED LINES USEDWITH ELECTROSTATIC FOCUS PICTURE TUBE, Pld FOCUSUNIT OMITTED.

3. SOME MODELS USE DUAL SPEAKERS.

A. RESISTANCE SHOWN IN BOB IS RESISTANCE OF WINDING.WHEN REMOVED FROM CIRCUIT.

TUNER A C. C

V7B

6SN7GTHORIZ. A.F.C. CONTROL

4.7 mE6.6.._

R-60.0022 MF

C-62

12BH7VERT. OSC.

OUTPUT

VERT. BLOCKINGOSCILLATORTRANS. T 21

9206,

R.d% I 57 00.H_SW

VERT. HOLD

6* *A1110,000 .6.. ER -102 750

VERT. Lill..n.

STOP AT 2506

6SN7GT j1..\2vHORIZ. OSC.

6W4GTHORIZ. DAMPER

---f120v

77.I IR-i0L

5 MEG,.VERT. SIZE

STOP AT MEG

100006,

B -NO

Vii

6CU6OR

6B06GTHORIZ. OUTPUT

2

'9,

VI45

7 II

V IC -100

140

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONV5 V6 V7A V8

6AU6 6AL5 -6SN7GT 6W6GT4 5MC SOUND I.F. RATIO DET. AUDIO AMP. AUDIO OUTPUT

O

O

8O

.005 is.

C-62

RATIO OET. COIL

C -6i

0

C-66

A 101 kW

470,- 33.0R-57 R-60

005 MfR

VOL. CONT_

68,000.,

63

SEE NOTE 1

-J

2700 50,1w 265 v

°P114 57E00E7

IIt O

22 000,

V12

005

LOCALITY ADJSWITCH

SW .I

WEAK SIGMEDIUM SIG.STRONG SIG.

SHOWN IN STRONGSIGNeL POSITION

1B3GTH.V. RECT.

H0R12 OUTPUTTRANS T-10

3130,i

IT

5

"^ITH

21

3T

2 5,1

35,

6.8,

.00000,5-96s

PM FOCUS

2 .0

UNIT

R-95

MF6

C -S. /

DE LOTION YOKET -P9

220000,,8-98

,5,000v

V18

SEE NOTE 2

220u,

R -u 0

VERT )UTP0TTRANS T-22

780.,T

12'1

AWAY*,5-109

300

R-109

6C MF

2

r

SEE NOTE 3

Sentinel013

5U4GRECTIFIER POWER TRANS T-20

29,

O,

L -

FILTERCHOKE

IP( 0-0600 "L-22

100 MF 60 ME

C-,01

TO 6W4GTFIL

-.I ----

FIG. 3

141

VII


Sentinel TRIMMER LOCATION AND ALIGNMENT CONNECTION POINTS

60.8

STEP- 4T4 VIDEO I.F.

T -I3 ANA MC

43GCB*

I sTEPT 244 VIDEO I F

-i$ 9.4 MC

OH STEP -3 TRAP STEP -5 344 VIDEO I.F.T it 43 2 MC

I STEP 10 KT VIDEO I.F.T-10 45.75 MC

9STEP -I SOUND TAKE OFF

COIL 4.5 MC T -IS

T 16

STEP -2 SECONDARY OFRATIO DETECTOR

T16 5NC

641:GT

O

STEP -9 Tu.,. I.F.. 44 5 .AC

1.2 SEE NOTE 6ADJUST FOR MINIMUM4010 INTERFERENCE ciNEZEIIIRD

SPEAKER1111INLS

SEENOTE

O

6T4

OTT AL,4/6491: T

STEPS II it RF AL.OSCILLOSCOPE CONNECTION

STEPS II it RF ALIGNMENTC3, C-4, C -I2, C -IS

(Continued)

5

MODELS

1U-701 1U-7551U-711 1U-7581U-714 1U-7621U-721 1U-7651U-724 1U-7681U-752 1U-791

STEP 3 CONNECT SIGNALGENERATOR TNRU VCR MEDCOND. TO JUNCTION OF C -NIS CATNODE OF PICTURETUDE .3 YC

STEP I PRIMARY RATIODETECTOR T-16 4.51,1C

STEP TNRu I CONNECT3 VOLT BIAS TO JUNCTIONOF C49 A R46 POSITIVESIDE TO GROUND

STEPS 'NOW 10CONNECT VOLTMETERTO JUNCTION OF-IS AND 11-,14

STEP I AND 2CONNECT SIGNALGENERATOR THI.A .001 MED. COND.TO JUNCTION OFL -I4 ASO L-15

C-69

R-60 T -i0

STEP 0 TRAP PART OFVIDEO I.F. T -I1

2A25 ML

STEP II TRAP PARTOf 3. VIDEO I.F.T12 41.25 MC

STEP 2 TNNU T,000 ONORESISTOR CONNECT VOLTMETERTO JUNCTION OF C..69 AND R-60

STEPS I 3 THIN, 47,000 ONRESISTOR CONNECT VOLTMETERACROSS C-66

0 0

FIG. 5

J

FIG. 6

142

HEIGHTCONTROL gaif!5`. LIWINN9

AMPL. CONTROL

6SN7 GT

F CHORI2. 05C

LIMITERDETECTOR15 AUDIOAMPL.

4.5 MC.MAPLE

SOUNDSYNC TAKE -CifAMPL. 4.5 MC.


SentinelSee pages 146-147 for circuit diagram, and page 148 for alignment.

HORI2. DAMPER

10925CU6

GT

HORIZ. OUTPUT

STAGECOUPLI

P143VERT

HOLD

14464HORIZ

LD

CONTRAST1

RI20

FINE

TP21

TOI L9

arcs

-71010

DETEC

<

7105AUDIO

OUTPUTTRANSFORMER

MIXERCOUPLING

re N)

BRIGHTNESS1013

CONTROL FILTERCHOKE

VIOEI25L6

GT

AUDIO OUTPUT

FRONT VIEW OF CHASSIS

R126BRIGHTNESS

CONTROL

C21

-

P 1010 1 INTERLOCKC

I RI46VERT LIN 0CONTROL 1

VERT OSC ao I I "EIGHT

vEll AMPL11 CONTROL

12 0,17

k

\/ r-/- -/' \ \ \ \

/ , \

1-F AMPL6C86

L10125 1MC

ECOUPLING

",.\.\ -- ----- - - - - ----------- ---\\ \\ N

5

/ 1.

,'--o , L106

'AFC 1ZsBIZ OSC 0CI 42 I LIMITER OCT OuADRATURE

I B AUD AMPL a COQ.

1------_Jk46TYN

L7\

MODELS

1U-901 1U-921

1U-911 1U-924

1U-914 1U-991

HOR,Z DAMPER 1

1 220,4

HOR1ZOUTPUT

V x1 21 26

NVRECT

1

T 10E1

14101HOR,ZLOCO

qET - -\-- '&10,2E1 IL102 ,,..E,D,_F AWL 24 4MC OCT -L109

SOUND TRAP\

2 5.5MC 2 I RAID DET COUPLING 45 MC 10/ 1 GAMS a 1 4 5MC

-- 1L1034t* -ff

RI32/

I1 , 4 5 MC AMPL GIT

L-0

29MC-"---7:7/10 AMPL a SYNC AMPL I

2ND i-F AMPL \ I \ 6ANB i4 ; jauz z6CB6

r,iAU

CONTROL

SYNC CLIPPER EI

RI43

VERT.HOLD

R164

HO RIZHOLD

RI35

OFF-04-VLUMEO

R120

CONTRAST

STATIONSELECTOR

FINETUNING

REAR VIEW OF CHASSIS

(Tube & Alignment Locations & Tube Filament Wiring)

143


SENTINEL RADIO CORP,

REMOVING CABINET FROM CABINET BASE(TABLE MODELS ONLY)

1. Remove all control knobs and cabinet back.2. Remove antenna terminal plate from cabinetand disconnect speaker leads.3. Place cabinet face down on a soft clean cloth.4. Remove ONLY the cabinet mounting screwslocated under and on the outer edges of cabinetbase. DO NOT REMOVE CHASSIS MOUNTINGSCREWS. Remove the 2 wood screws from thelower rear corner support braces of cabinet.5. Carefully guide cabinet and cabinet base toits normal upright position. Remove cabinet bylifting straight up.

MODELS

1U-901 1U-921

1U-911 1U-924

1U-914 1U-991

THE PROPER ADJ.SCREW FOR THECHANNEL TUNED TOWILL APPEAR HERE.

Provide markers as shown on curve.

21.9 MC.

98%

[ tMC.

4_%

NOMINAL OVERALL I -F

26.4 MC

25.5 MC.

ol4 1(470

4

6 %

R1011-'vwv

C102

1(470

R102

47QK

RI53

REMOVING CHASSIS BASE FROM CONSOLECABINETS

1. Remove all knobs and cabinet back.2. Remove antenna terminal plate from cabinetand disconnect speaker leads.3. Remove the screws under guide rails of chassisbase and the one screw under center supportbridge.4. Slide chassis base out.

6BC5

V2

VHF R -F TUNER

2

R105700

8104

8152

7 5SEE NOTE 7

RED

1000

V1016C86

SST PIX L10225.5MC

42V,

91075 10K

6

004J25v, k),201

R106 RI0947 1000

-11

R108NAN`

C103__ 4700r001

005

RII01000

V1026086

280 Pix IF

005MFD

RII2

R111

1000

68

L103

11

VI91

456An

219000101

22 9NC

C106

T.005F0

AGC

R103AWN,220

L108

00000V -L-22V ,P

SRI01 30's C132R ° 79 P -P

200NIFD

0139

6U6V2

040C

R. F TUNER

200MFD 0.2V P -P

68C5VI

4 3

QAX4 25CU6VIII V109

8 7

432

25L6V108

1AL

RI54

6C86V101

4

G129_

INW0K

220E

1.25 TTTT MEG

2I

45V. P -P

6%2642 6/I'6AN 8 6U8V104 V105

RI38MEG.

j.1691

V1048Y26A1.48SYNC.

CLIPPER

12887

3 5 4 S 4 5 4

43

NOTES'

I ALL VOLTAGES MEASURED WITH AN ELECTRONIC VCI_TMETERCONNECTED FROM SOCKET LUG TO CHASSIS, SEE FOOTNOTE

2 SUPPLY VOLTAGE 117 VOLTS 60 CfCLE AG3.K 10004 ALL C,APACITANCE VALUES IN MME a ALL RESISTANCE

NILUES IN OHMS UNLESS OTHERWISE NOTED5 LUG 3 CONNECTED TO BOOST VOLTAGE a LUG 3,885

CONNECTED INTERNALLY.

6.C134 MAY BE EITHER A.047 OR .033 CONDENSER.ALWAYS REPLACE WITH SAME VALUE CONDENSER.

7 ALWAYS USE EXACT REPLACEMENT FOR R -I5 2,A 7,5 OHM FUSIBLE RESISTOR

SOME vOLTAO6 ARE VARABLE At VOLTAGES 940. AtRE MEASUREDM11H NO., INCIIRE ON THE PGTURE TUBE IWO THE CONTRAST10% C. Nvo 10650 NESS awn°, so' FOR SO DOLTS PEAK TO PEN) ONTmE cArriCOE (RN m 1 Of THE PiCTsv, TLEIE.SOOKET VOLTAGETOLERANCE! 10i.

RESPONSE CURVE

2 7;TE7-irl,i

L107

68N6V106

0155

r80156

TatRI74(266

L102 L103

i-Lt4T,N6

0141

C130]

I7V.

81394713

35

7-20

7svP46SN7GT 21ATP4

10 107 V113

LI 09

LOCATINGLIP

144

IMOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONSP 01

V106ow( 7105

CA21 LI II LIMITERDETECTOR

CAu911281 tg66N6. 470 2V5L1086GT

OUIRITBAJDi0 AWL 02

MFD.

I lovl C1251260v

4.PM. SPEAKERRED

C12 .095POD

MFD. R131)18K

2 601

RI32500

BUZZCONTROL

P134

L106

0124 iiiMED

TR

T5

-C-1 C126T.001MFD.

3135 GIST330K 2

MFD,ccVOLUMEcL

142v

z 5v

1.150vr RI36

4R137

706

560K

V103A V1038)060M8 TIOI 126Am8

3110 FIX 1-F 24.4140 RID. SET

10.14601

9, 1...14Ew I6 0 ii

P115_- Aw.,

l000

1 +.1.0 0109

-

. 00501081 MFD1-005 0114 7" R116 CHO

MED 100 10007.

E5'701 L104

ago37"

C112

10T

clod_T5

C111

11118

566

CII6

0 r

IMEG. VIDEO AMPL.Y26AN8V104A

_1000 L.

....\1+2111,4 1.41-CII5 33 LII2 < CII7 wv"

0113 911 L.1.: 71.1

eV(L---4 nr=i (0, ''Tu"-,R

U

MFD. .P.31v1

MFD 217.1,g . - 276U:,T<3V P -P

I.75MFD 1

_1_

o

336 3

L105

io To 2t,js

R12147

!Im

4._____

la) RI 24

=

RI 26Amm

BRIGHTNESS7 15005 66CONTRAST

1ggMriRotCONTROL

111258.26

j,{r moot

PiCTuRE TUBEVI I 3

11 6

1«15001

)26ov

1140.66

_

= VI0513426028SYNC.AMPL.

1.141V

47K

CI31_

0132A-_:RI42

000

22 706 ,10191_MED.

OOb .01

MFD NE

300 p -p

RI64145K

71:3( 5 02Kea. HOLD

3

ELL( TI06 y0,0%,

65V P -P

RI43i MEG. - VIIOA3605 ', vERT,STOP Hol_D, 112128H7

CONT. VERT.DSC.

C134_47047 11:1,.v.

MFD

, SEENOTE 6 3

25 MEG

imEG. STOPHEIGHTCONT.

CI43

R---)1 00

0142 NOR1ZLOCK1

6

81595606

1.4 P -P 81601506

2

276

R166 P1671006 1506 I'6"'

0146 1108

FM.8,

3

2.7mEG.

V107AF265N7GT

HOW. AFC.

i6161 11162 P163I50< 1006 826

0244 C1451

TOWINAL 00C31E113

T108

I 4

2 3

T 101

2 3

RED DOT

TIO9

-25TWD MFD. V1078Y26SN7GTHORIZ 0Sc

9:

-9001

T107

R169o8K p4-^

io

C1471E111

OIMFD

375,

p -PC1491

I3000150

CAP

R170470K

V10925C U6

1161112 OUTPUT

0173

100

OVER

P -P

ELLE

VII0 BF2128M7

OUTPUL

31400

6

RI47750VERTLIN.

0137

014B

T107 4

on 680GREEN -TEL

500.,EL. C136

1.005MFD.

1_10 7-AGRN-BLACK - 7

0156: T4.....,c)680, ,4'6

51MFD

7 51(

Ri57, c;

C14

30C138 -

20MED.

SEE NOTE 5.

3100PP

RI5039

RI5 I820K

CI51

-1.111000 P P

I p0AL

VIII12AX4

DAMPER5

C152 09.

182P o4 5

260 vI

FOCUSIt may be possible to obtain better focus with re-placement picture tubes, if the electronic focusanode is connected to a point other than the +150volt line.Suggested points to try are : chassis ground, +260volts, +285 volts (picture tube pin 10) and +480volt line.

V1121028

RECT.

71T109

6

g'T.

3 CI53<7, 11 I

.068I CI54

0

1417k5IFD. -7-6fl? 4 700 '4,

4 GREEN

I

)«48001 - p(15 BLALS

I 3KV.1

L107-13H OR IC.DEFtYOKE

145

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONSentinel Radio Corp. ALIGNMENT DATA Models 1U-901, etc. (Continued)

CAUTION: One side of the chassis is connected to the power line. Therefore, test equipment should not be connected to thereceiver unless an isolation transformer is used between the power line and the receiver. DO NOT GROUND THERECEIVER CHASSIS UNLESS AN ISOLATION TRANSFORMER IS USED.

The front side of the chassis as referred to below means the side opposite the tubes.

SOUND ALIGNMENT

StepNo.

Connect SignalGeneratorThrough a

.01 Capacitor


ConnectVTVM

Miscellaneous Connectionsand Instructions Adjust

I Cathode of Pic-ture Tube

4.5 mc. Across second-ary of outputtrans. 1105.

Use a high input level on signal gen-erator.

Adjust 1109 (rear slug) for minimumreading.

2 Pin 8 of VI04. 4.5 mc.FM mocklated400 c.p.s.,25 kc.deviation


Set Bun Control (R132) to approxi-mately 90° from clockwise stop. Setthe Volume Control (R135) at a lowlevel.

L106 for maximum reading.

3 Pin 8 of V104. 4.5 mc.FM modulated400 e.p.s.,25 kc.deviation


Set Bun Control (RI32) to approxi-mately 90° from clockwise stop. Setthe Volume Control (R135) at a lowlevel.

LI II for maximum reading keeping in -put signal at a low level (below limit -ing).

4 Pin 8 of V104. 4.5 mc.FM modulated400 c.p.s.,25 kc.deviation


Set Buzz Control (R132) to approxi-mately 90° from clockwise stop. Setthe Volume Control (R135) at a lowlevel.

L109 (front slug) for maximum readingkeeping input signal at a low level.

5 Pin 8 of V104. 4.5 mc.AM modulated400 c.p.s.

Across second-ary of outputtrans. TI05.

Use a high input level on signal gen-erator.

Bun Control (RI32) for null (minimumreading).

6 Pin 8 of V104. 4.5 me.FM modulated400 c.p.s.,25 kc.deviation

Across second-ary of outputtrans. TI05.

Set the Volume Control (R135) at alow level.

Re -peak L106 for maximum reading.

I.F. ALIGNMENT

StepNo.

Connect SignalGeneratorThrough a

.01 Capacitor


ConnectVTVM

Miscellaneous Connectionsand Instructions Adjust

I Test Point No.2 on Tuner(closest to L9slug adjust-ment).

24.4 mc. Junction ofRI 18 and C113and chassis.

Connect 3 volt bias battery negativelead to white lead from tuner, positivelead to chassis.

TIOI for maximum indication on meter,limit input to make peak less than -2volts D.C. on VTVM.

2 Test Point No.2 on Tuner(closest to L9slug adjust-ment).

22.9 mc. Junction ofRI 18 and Cl 13and chassis.


L103 (rear slug) for maximum. Usefirst peak from tinnerman clip end ofcoil.


21.9 mc. Junction ofRI 18 and Cl 13and chassis.


1103 (front slug) for minimum. Inputlevel should be high enough to produceat least .5 volts at null on VTVM. Usefirst null obtained from end of coilform opposite tinnerman clip.

4 Repeat steps 2 and 3.

5 Test Point No.2 on Tuner(closest to L9

slug adjust-ment).

25.5 mc. Junction ofRI 18 and CI 13and chassis.


L102 for maximum.


25.1 mc. Junction ofRI 18 and CII3and chassis.


L101 (front slug), for maximum. Usefirst peak from tinnerman clip end ofcoil.

7 Test Point No.! on Tuner(closest to C2Itrimmer screw).

25.1 mc. Junction ofRI I8 and CI 13and chassis.

Connect a 100 ohm resistor in serieswith a 1000 mmf. cap. across LI01.

L9 (brass screw) on the Tuner for maxi-mum.

146


Sparta CHASSIS TYPE 23U214THE SPARKS WITHINGTON COMPANY - JACKSON, MICHIGAN

SPARTON Models 11T210, 12A204, 12A210, and 14A204(Circuit diagram on pages 148-149; see page 150 for data on Standard

Tuner used in these sets.)PICTURECENTERINGTAB

FOCUSCONTROL

WING NUT - YOKEPOSITIONING (TILT)

IONTRAP

DEFL,ECTION YOKE AND FOCUSUNIT ASSEMBLY

Ion Trap and Focus1. With brightness control set for low brilliance, move trap forward or backward and at the same

time rotate until maximum brightness of raster is obtained.2. Readjust raster brilliance to normal.3. Adjust focus control until best picture detail is observed over entire face of picture tube.4. Readjust ion trap once more for maximum brilliance.THERE MAY BE TWO LOCATIONS WHERE ION TRAP WILL PRODUCE BRILLIANCE ON CRT;USE ONLY THE POSITION NEAR THE CRT BASE SOCKET; NEVER USE THE FORWARD POSITION

Deflection Yoke1. The yoke must be held firmly against the flare of CRT.2. To level picture, loosen and adjust wing nut on yoke.

Centering Raster1. Center with magnet control tab on focus unit.2. Readjust ion trap for maximum brilliance.

Picture SymmetrySometimes linearity and corresponding size controls may have to be re -adjusted. A test pattern ismost practical for these adjustments which consist of HEIGHT, VERT LEN., WIDTH, and HOR LIN.

Peak Performance Control1. With receiver operating, set the peak performance control to extreme counter -clockwise position

(fringe area).2. Tune in strongest signal in your area.3. Set contrast to maximum (extreme clockwise position).4. If picture appears normal leave control set in fringe position.5. If picture shows any signs ov overload, rotate control clockwise towards local position until

picture becomes normal.6. Do not turn control toward local position any more than necessary.

Horizontal Oscillator (Make only when necessary)1. Pull 6AL5 (phase detector).2. Set hor. hold to center of range.3. Shunt L47 with .1 MFD 400V condenser from test point on high voltage transformer to ground.4. Adjust R133 until picture floats in horizontal sync.5. Remove .1 condenser and adjust L47 until picture floats in horizontal sync.6. Replace 6AL5.7. Pull -in should occur when 2 or 3 diagonal bars are observed as hor. hold is rotated towards

center of range.FOCUS ADJUSTMENTS:Under certain conditions the focus may be improved by adjusting focus unit mounting brackets tolocate the focus unit approximately 4-1/4 to 4-3/8 inches from the base of the picture tube (meas-ured from the end of center locating key of duodecal base). With the ion trap set as previouslydescribed, adjust the focus control for best overall picture detail.

CAUTION: READJUST ION TRAP AFTER ALL ADJUSTMENTS OF FOCUS.

147

MOST -OFTEN -NEEDED 19SS TELEVISION SERVICING INFORMATION 1

1SPARTON TELEVISION SCHEMATIC DIAGRAMPr201=C'

1C -L3

,ocAL vL NT(1).

CAI VE

NOR N.

EDDINTERLOCK

MOT..

CHASSIS BACK VIEW

0 0

POWERTAANYORMEN

0 )0656470TA

57307

VERTICALAL

3C. 'PANS

O 6V607

TOP VIEWSATS

UTTRANS.

SC136

C).11.M.L6

12A1.17

IC.0.4405TEv.. rLNLRNT N4

674 .7:i-LJ

12677 4.30 L.5I

t(1.i1.1 VLtssE

6C1312

IoI.0. °

7j- BOTTOM VIEW11=1' C1313

LEI=

I

0 00

4D 0

VP,

I B307

49,. 13CD6015AXMIT

0000CO3

CONE. CONO. CONO

12AU7

655707*

CHASSIS TYPE 23U214 MODELS IIT 210 , 12A204 , I 2A 2 10 , 14A204

COMPO,ITE

TUNER

IRON CORECHANNEL 2 MIK/ 11

La

LtU.H.F.ANT. D

IU.N.F. DRUMSEGMENTS

'I°

LIP

°15- \

OSC.ADJ.

OR

VI6827

CPO.500

BANDWIDTH SETCOUPLING LOOP

V26U8

4114:33,1 .O,To A.G.C. 250 0.C .5

1003

ItI

+125V.

I. F. CORY.3. LIC34 C33 CONNECTION

00 P-2ma0

CD Lea

C37

P-1POWER

PLUGLOOKING ATPLUG PINS

OF Y2T

43.1 MC

j.341MC.I.F.

UPS , OUTPUTRECEPTACL

NO

LOOKING ATTOP Or SOCKET

J-1

P-3IMC.

INPUT Cijj.-- -PLUG

C

N IITC i.F. COILSSWITCHED IN FIRU.5F. RECEPTP N

If. COAX.CONFECTION

2

OPEN

220011331(

YELLOW WIRETO WEARER

REMOVE/WARMPOR 4 WAYCOMBINATIONS

A.G. SWITCH ONVOLUME CONTROL

A.G. TAKEOFFCIS FOR C OIMINATIONS

TILT vCAR. 6 SN7074. OS

631470T GA 540K

CA:13-4

VOLTAGE TEST SPECITICATIOWI. ALL VOLTAGES CURRENT MEASURED IN VW POSITION - CHANNEL 2.1. LINE VOLTAGE - 117 VOLTS A.G. NO SIGNAL INPUT APPLIED TO SET.3. BRIGHTNESS CONTRAST CONTROL POSITION - MAXIMUM CLOCKWISE.4. HORIZONTAL VERTICAL HOLD CONTROL POSITIONS - SET CORRECT POSITION TO LOCK IN

PICTURE.5. WIDTH CONTROL POSITION - SET FOR NORMAL SIZE.S. VERTICAL SIZE A LINEMUTT CONTROL POSITION - SET FOR NORMA.. SIZE BEST LINEARITY.7. VOLUME CONTROL II TONE CONTROL POSITION - MAXIMUM COUNTER -CLOCKWISE.S. INSTRUMENT (METER) USED - (VTVM) VACUUM TUBE VOLT METER.I. UNLESS OTHERwillE DESIGNATED ALL VOLTAGES MEASURED IN RESPECT TO CHASSIS GROUND.

INTERLOCK

T-6POWERTRANS.

V.A.C.SO

COMPOSITE TUNERVI

V235Y3GTL. V. RECT.

L- 32

200 MA.S VOLTS3 AMP.

S E VOLTSE S AMP.

6.3 VOLTS VT, VS

2V22

*125 VOLTS

W4OVI X4/0 I WA*Ia50V 450 V. ITS V.

Mir

PERFORMANCECONTRO

+ISO VOLTS100 MA

.300 VOLTS

.1

VI6B6SN7GT

6SN7GTAPHA SE

SPLITTER

,

3 3

_ C1,12

04 VS vS Ve va 511 VI2 VI3 VI! VIS V17

1,^4 r' rHEATER HOOKUP DIAGRAM

14.8

C41

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONVI4

6V6GTPOWER AMP.

VI 06AU6

It! BOUND IF

5V

L30 V46CB611/ I. F. AMP.

MICA

CI22

MICA2K

010 V20

22001

PP

VI86AL5

HORIZ.PHASE DET.

DIAL LIGHTTYPE 47

TO 0.3 VOLTS

VII6AU6

2M12 SOUND I.F.5V is, a

2 0v

5/42.

22

CM

L3I V56CB6

the I. F. AMP.

VI5I 2AU7

SYNC. STRIPPER,AMP. t. CLIPPER

A C124

TANj1.10012

OSC.

V196 SN7GTAHORIZ. OSC.

& DISCHARGE400V

5012.7

0 T°. TERMINAL TAIT ON T-

25.4 gAre

1214 7214RI31 RISO

T-3

V12 VI36AL5 6AT6

RATIO DET AUCIO AMP.

VOLUMECONTROL

07150 VOLTS

L32r

1 46

C103A 1036

110RI2HOLD

:11

V76AU6A.G.C.

T I 12BYV87VIDEO LIMP.

CS.

11 11

V I6A6 SN7GT

6 SN7G TAVERT. OSC.

1-5 I. DISC. TUBEVERTICALBLOCKING 00

OSC.VELLOM 41[14

CD

V66CB6

361/ I.F. AMP

27011RRMAAV

014

VERTICALMOLD

sie CI20. MA1e

VW TITS V.

NOTE: FOR 214P4EI PICTURE TUBE, JUMPERWIRE CONNECTS, AS SHOWN, FROMTERMINAL 415 TO 31).FOR 112.174A PICTURE TUBE, JUMPER

p

10vo WIRE CONNECTS , AS SHOWN BY BROKER

LINE, FROM TERMINAL 46 TO 4111 ANDC134 IS OMITTED. 21+0 ANODE VOLTAGEIS THEN ID RV.

NOTE.The paints 1.3[21. by 1. num.rs I 2 3 4 5 6 4 7 are the alignmenttest ,ints referred in the alignment procedure.3 Pin e2 of V2 1611510NT. Mixer Tube.

Apply stignals for spot and sweep alignment of converter stage.2. For Tuner alignment Oct,3. Diode load reatator

Read D.C. output .re for SRO, - Mtg....Connect scope .re for vtsual 1.7. alignment

TO POINT XON V7(ewue)

G4300 VOLTS Aral

4. Cathode ofCPicture TubeRead A.C. output here uturall senIttivt,Connect

refor 4.5 Me trap alignment

5. Rat. Detector OutputRead D.C. here for alignment of suu. lake &I trap, tnt Ee 'Lind

F. transformer and pron., of ratIn detettor transform6. Ratio Detector Balancecl Out

Read D.C. here for altsnment of serond.,r, of italic detector trans.

7'K CONTRASTCONTROL

V176AH 4GT

VERT.OUTPUT

COMRIOT 100.43

SOV

Id V

00012. SET

A

270ROI

4/4V1F

+3400.

V92IZ P 4A

OR

2IZP4B17 BP4A

PICTURETUBE 4N RY

T-6VERT. OUTPUTTRANSFORMER

Tti-LOw

600 VOLTS

2tIG ANODE

100V.

100K

442..BRIGHTNESS

CONTROL

V21I B3G TH . V. RECT.

I KAP.

am TO SOANODE

V226AX4GT

DAMPER

L-49

L-50NOIRE.LINEARITY0.444

101

L -48A(zalvt;L-46VERY,YOKECOIL02,4

".'w" OL-465

L-51%MOTH

CONTROL

(zar../10L-46 D( row

)NORIZ.TORECOILIS..

CiMMOM

0011.

NOTE ADJUSTMENT OF CONE" .S.1, BRIGHTNESS,VERTICAL SIZE, HOF,LONTAL HOLD AND ROM, ,ONTAL DRIVE CONTROLS WILL CHANGE, VtILTAGESFROM THOSE INDICATED IN THEIR RESPECTIVEASSOCTATED CFRCUPTS.

WAVE FORMS TAKEN WITHCONTRAST CONTROL ADJUSTEDFOR SOV, P to It at PIN of VS,

149

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONStandard Tuner used in Sparton Chassis 23U214, continued.

o.wn<-

N

0 Z <

0

0

a)eo

CakEcE

be 0

C.)

o (1.)

E-4

a)

0.

0

Cr)

R. F. Tuner.Figure 1 shows an exploded view of the composite Standard Coil tuner. It can readily be seen that separ-ate UHF and VHF assemblies have been combined mechanically and electrically to form the complete unit.Three concentric shafts are used to drive all of the UHF/VHF switching and tuning elements. Of these,the inside shaft rotates a 12 position VHF turret assembly and, ganged to this same shaft, three cam shapedielectric sections that tune the UHF decade coils through the UHF digit positions. The center shaft ro-tates the UHF decade turret and with an attached double action cam tilts the 45 MC I.F. rocker bar intoposition for UHF operation. The third or outside shaft drives the ganged VHF and UHF fine tuning cap-acitors.Block diagrams A and B show how the tuner circuits are arranged in the VHF and UHF positions.The antenna circuit of the VHF portion contains resonant circuits L2 -C8 and L3 -C7 which are fixedtuned for maximum rejection of interference in the I.F. band. ,Circuit C9 -L10 can be variably tuned toprovide additional attenuation of any specific interfering signal in the 35 to 48 MC region. Remainingcircuitry in the VHF section of the tuner is similar to that found in the straight VHF version, exceptthat a pentode triode (6U8) is used as the VHF oscillator mixer. The coupling circuit between the mixerplate and 1st video I.F. stage is described in the video I.F. section.A separate UHF antenna input is provided on the tuner. This is connected to capacitors C30 and C31,which together with coils L20 and L21 form a high pass filter with a cutoff frequency just below theUHF band. This system attenuates I.F., VHF and other interfering signals before they can enter theIN82 crystal mixer circuit.The remainder of the antenna circuit consists of a portion of the UHF decade coil assembly (D on theschematic diagram) plus trimmers C33 and C34, choke L6 and capacitor C164. Tuning coils L22 andL23 are connected to capacitor blades which are imbedded in the coil board assembly proper (see item64 to 71, figure 1). UHF channels within the range of a particular decade coil are tuned by movementof cam shaped dielectric sections which mechanically fit between these capacitor blades. To cover theentire UHF band eight separate decade coil board assemblies are switched in and out of the circuit byrotation of the UHF turret assembly (item 57, 58, shown in figure 1).

150


STEWART-WARN ER MODELS17T -9620A, 17T -9620B,

21C -9630C, 21C-9630CB, 21C -9630D,21T -9630A, 21T-9630AB

Circuit diagram and other service information is printed on pages

PRODUCTION CHANGESThe following tabulation furnishes complete details on changes which occurred during receiverproduction. The chassis circuitry can be established by referring to the serial number labelaffixed to the rear of the chassis and then checking the tabulation below. The starting serialnumber is shown for each group of changes. Unless otherwise indicated, chassis bearing serialnumbers of a high order will contain changes listed under lower order numbers.

A letter fol'owing the component circuit diagram number thus -201A. indicates that thisitem was affected by a circuit change and is used only for circuit diagram reference.

SERIALNUMBER DESCRIPTION OF CHANGE

104,601 Initial Production

106,601 The following change was incorporated to reduce drive bar and affectedcomponents have circuit diagram reference A.

I. Resistor 169 was added between the center tap of the power trans-former 63 and chassis ground.

2. Resistor 106 in grid circuit of tube V10, Horizontal Scanning Output,was changed from 470,000 Ohms to 330,000 Ohms.

106,701 The components affected by the following changes have circuit reference B.

The following change was incorporated to provide a longer antennalead-in.

1. R.F. Tuner part number was changed from 522514 to 522931. There areno electrical differences between these two units.

The following change was incorporated to reduce radiation of harmonicfrequencies being fedback through antenna lead-in.

1. Tube shields were added to the three I.F. Amplifier tubes V3, V4, andVS.

2. Antenna lead-in was d r d against side of chassis and antenna termi-nals were lowered to lower part of cabinet.

3. Resistor 168 (15,000 Ohms) was added across primary of 3rd I.F.transformer.

4. Peaking Coil 167 was added between detector 40 and condenser 44.

The following change was incorporated to facilitate production.

1. Power Transformer 63 part number was changed from 522677 to522973. When latter transformer is used, resistor 169 is no longer re-quired, therefore, it was omitted.

2. on trap, 60 part number was changed from 521183 to 523001.

The following change was incorporated to improve the taper of the Picturecontrol.

1. Volume and Picture potentiometers, 46-A,B,C part number was changedfrom 522515 to 522744. When the latter control is used, resistor 47 isno longer required, therefore, it was omitted.

CONTROLS

'522744 VOLVOL 8c PIX POT. ( INCL. ON -OFF SW.)A -PIX ( 1500 OHMS r< WATT)B- ON- OFF SWITCHC-VOL. ( 1 MEG. WATT)

2.50

(USED IN CHASSIS BEARING SERIAL4 6 A r^I NUMBER ABOVE 106,701)

.5---2-2515 VOL & PIX POT. ( INC t. . ON -OFF SW.)

B- ON- OFF SWITCHA - PIX ( 3000 OHM k WATT)

C-VOL (1 MEG . ,i. WATT )( USED IN CHASSIS BEARING SERIAL( NUMBER BELOW 106,701)

59 520652 BRIGHTNESS POT. (100,000 OHM) I.001 9 52-2349 VERT . HOLD POT. (1

152-153.

GRAMNO.

NO.

DIA-PART DESCRIPTION

LIST

PRICE

COILS AND TRANSFORMERS

c J520977 TRANS. 1ST VIDEO I.F. (LESS SLUG) .75k 507357 SLUG CORE. 1ST VIDEO ICOIL .20)522791 TRANS . 2ND VIDEO I .F . ( LESS SLUG)

3 2 ( C ODED RED DOT) .80(507357 SLUG CORE, 2ND I.F. COIL 20

522703 TRANS. 3RD VIDEO I .F . ( INCLUDES39 CRYSTAL 40, COND . 41, PEAKING

COIL 42 & 167, RES. 43 & SLUG) 3.500357 SLUG CORE , 3RD VIDEO I .F . COIL .20

42 520985 COIL-PEAK/NG ( DOUBLE PI CODEDWITH GREEN DOT .65

)50960311.5

MC TRAP (INC1UDES SLUG &4B CONDENSER 49) 1.20

1;07357 SLUG CORE,TRAP COIL .2050 20689 COIL -PEAKING (SINGLE PI CODED

52 509342 COWITH _D0T1IL -PEAKING ( SINGLE PI CODEDWITH YELLOW DOT)

522973 TRANS. POWER ( USED IN CHASSISBEARING SERIAL NUMBER

63 ABOVE 106,701) 17 50522677 TRANS . POWER ( USED IN CHASSIS

BEARING SERIAL NUMBERBELOW 160,701) 1

65

65 22608 CHOKE --FILTER100 52251 TRANS . --SYNC ROG UIDE109 5224 9 TRANS .- --HORIZ . OUTPUT

.60

.503.509.50

118 509378 TRANS. ---AUDIO TAKE -OFF 1.50124 509706 TRANS. UND DISC. (INCL. COND.

124A &124B) 3.00142 509176 TRANS. ---AUDIO OUTPUT 1.85146 522674 TRANS.---VERT. OSC. 2.25161 522144 TRANS.-..-YERT. OUTPUT 4.00

(522924 YOKE. PIX TUBE DELFECTION (INCL.COND. 116 & RES. 1611 & 165)(USED IN CHASSIS BEARING

166-A.B SERIAL NUMBER ABOVE 106,701 10.00522699 YOKE, PIX TUBE DEFLECTION `IN L.

OOND. 116 & RES. 164 & 165)(USED IN CHASSIS BEARINGSERIAL NUMBER BELOW 06,701) 10.00

167 509340 COIL -PEAKING (SINGLE PI , CODEDWITH WHITE DOT) (USED INCHASSIS BEARING SERIALNUMBER ABOVE 106,701) 55

52070233 3

COIL -ANTENNA CH. 2 CODED 2Q 1.052070 COIL-ANTENNA CH. CODED 1.40520704 COIL -ANTENNA CH. 4 CODED 4Q9 1.40520705 COIL -ANTENNA CH. 5 CODED 5Q 1.40520706 COIL -ANTENNA CH. 6 CODED 6Q 1.40

bol_ 520707 COIL -ANTENNA CH. 7 CODED 7Q 1.15-- 520708 COIL -ANTENNA CH. 5 CODED bQ 1.1

520709 COIL -ANTENNA CH. 9 CODED . 5

520710 COIL -ANTENNA CH. 10 CODED 1 1.15520711 COIL -ANTENNA CH. 11 CODED 11Q 1.15520712 COIL -ANTENNA CH. 12 C DED20 1 COIL -ANTENNA Cl). 1 CODED 1 1.15

40 520701 COIL -CATHODE COUPLING .15520722 COIL-R.F. & OSC.

53

CH.32 CODED 2Q 1.

520723 COIL-R.F. & OSC. CH. CODED 9 1. 552072k COIL-R.F. & OSC. CH.45 CODED 4QQ 1.85eMELDI1.27R.F. & osc. CH. CODED 1.

520726 6 COIL-R.F. & OSC. cH..779

6 CODED 6o 1.85552072COIL-R.F. & OSC. CH CODED 1.70

413 520728 COIL-R.F. & OSC. CH.8 CODED 8Q 1.70520729 COIL-R.F. & OSC. CH.9 CODED 1.70520730 COIL-R.F. & OSC. CH.10 CODED 1 1.70520731 COIL-R.F. & OSC. CH.11 CODED 11 1.70520732 COIL-R.F. & OSC. CH.12 C DD 12 .7

520 COIL-R.F.CODED 139 1.70507 SLUG FOR OSC. COIL: ux. FINE

TUNING ADJUSTMENT .05

424 520714 COIL -CHOKE .15

426 520715 COIL -CHOKE .45

427 520734 COIL ---CONVERTER PLATE I.F.(INCLUDES SLUG & CLIP) 215

509062 SLUG CORE -CONVERTER PLATE COIL .12

-311

520518 COIL -CHOKE .10

44- 520520 COIL -CHOKE .10

151

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONSTEWART-WARNER MODELS OSCILLOGRAMS

All oscillograms taken with ground lead of 'Scopeconnected to receive chassis and controls set for

17T -9620A, 17T -9620B, normal reception. Picture control adjusted to give 42volts peak to peak at cathode of picture tube. Oscil-loscope vertical amplified response was flat to

21C -9630C, 21C-9630CB, 21C -9630D, within 20% at 2 MC.

21T -9630A, 21T-9630AB

EJNETUNING

616MIER OSC

6807.6807A111.241.11

646

641.16ITArLANP

VI

6607%16807ARI AMP

406

Of

ua

.:.

408 L__ 1_1

417

02

616MIXER OSC

4,6

409

OV

124

42

2

23

Number appearing to the left of oscillogram speci-fies setting of horizontal sweep frequency controlon 'Scope.

V]

66U61m I F AMP

c"" ; 1616

B"-

CHANNELSELECTOR

6605 '

SOIMO OUTPUT

GTSOUNOGRSCIMINATOR

SOUND ARP

611

FR

SANSWINO MAP

STNC SEPARATOR

112:11701

SYNC MAP 6411407

VERT BLOCKING OSC ROTTICA,Srmor.

VOLUMEOFF -ON

PICTURE

118P4

ITRP4OP

210P4om

21YPIAPICTURE TueE

11338T

176TITEr

680601ORIZERIOTutZTANNING

FUSE

4 AMP 250 VOLTLOCATED ON UNDERSOE

61N0TOF CHASSM

6SN7GT ... HORIZONTAL

NOW AF .0 WAVING

Mei SLOGANS OSC

VERT VERT TIORIZ VERT.HOLD LIN. HOLD SIZE

OPNMLK JHGFE521068 R.F. TUNER UNIT

(SHOWN WITH SIDE SHIELD REMOVED)

8

8

8p.

GS

X14

04

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VA

66662nd I F AMP

O

Al

20

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5AGRECTIFIER

44 aUN

)40

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V68

VAAN8SYNC. CLIPPER

T6 1Y I

6841

1/212687SYNC. AMP

rs

44,

A

IlewsAAAA,0

BLACK -WHITE

GREEN -WHITE

RED-wmaE

WHILE

BLUE -WHILE

60170m VIEW OF CHASSIS SHOWINGCONNECTION TO F TUNER Lora

YELLOW

IDENTIFICATION

D

1stI.F. Coil520977

RED

IDENTIFICATION

2ndI.F. Coil522791

I"'65

ovVOA, 9

)2AT

1

[440

310

L-6

19

1/14

66116SOUND IF AMP

LIMITER

0 124

n21 123[Imomu,

152

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONVOLTAGE MEASUREMENTS

All voltages measured with a 20,000 Ohm per volt meter with the receiver connected toa 117 volt 60 cycle power supply.Tuner set to an inactive channel with antenna terminals shorted and connectedto ground.Controls set fo, normal reception-Picture control completely counterclockwise.Voltages marked with on asterisk (e) will vary widely with control settings.All voltages shown, except R.F. Tuner socket measurements, were taken under theabove conditions.R. F. tuner socket voltage measurements were token with tubes removed from sockets.

115

66116Rd I I AMP

0 V 3

240

6T8SONO DISCRIMINATOR

SOUND MAP

04

429

To 39.

Ts nas jO

VSA

V4SSN7 CTHMG All

/I46845

SWAM output

V

Va6SN9BIGTNOW &OCRING

OSCILLATOR

NNVe:NF IBIT

200

42

145

VGA

I/264N6VIDED AMP

via

04 61106GTNIRIUONIAL SCANNING

MONT

VAG

1/4124117VERT 1110CRINGMAWR

146

FRT

s49

ydgoMOLD

STEWART - WARNERModels 17T -9620A, -B, 21C -9630C,21C-9630CB, -D, -A, -AB.

VIIIB3GT

MGR vLITTAGERECTIFIER

VIZ

6W4GTWIR12011141

DAMPING

nA14461

OUTPIP

vr1711P4

OP

I7RP4OR

21v P4or

211 P4AMUM -WA

HORIZONTAL DEFLECTIONWAVEFORMS

MSS Lt. ISOOV

VOLTAGEMem. ninS al mean

-1rs NN \IN

CURRENTlaser1 Girl. male, 01633. 3 4444 ,nries3134.41131..31.44 4333431

ura.. 0,4

VERTICAL DEFLECT..wAVCIOR S

...11.1# 90v

VOLTAGEman. Mem pm Ta 01 nom

CAREIMInmm anew% .434.34.3 ... anrCF

mac tn. C031.113.3..31/0,

II

153


STEWART-WARNER MODELS21C -9700W, 21C-9700WB, 21C -9700X21C-9700XB, 21T -9700R, 21T-9700RB

YELLOW WHITE

IDENTIFICATION IDENTIFICATION

1st and 2ndI.F. Coil520977

§ 75 66,66

pS

3rdI.F. Coil520979

414

5U4GRECTIFIER

VOLTAGE MEASUREMENTS

0

310

All voltages measured with a 20,000 Ohm per volt meter with the receiver con-nected to a 117 volt 60 cycle power supply.Tuner set to an inactive channel with antenna terminals shorted and connectedto ground.Controls set for normal reception-Power Booster control completely counterclock-wise.

Voltages marked with an asterisk (*) will vary widely with control settings.All voltages shown, except R.F. Tuner socket measurements, were taken under theabove conditions.R. F. tuner socket voltage measurements were taken with tubes removed from sockets.No voltage reading at a tube element indicates zero voltage or voltage which cannotbe accurately measured with a 20,000 Ohm per volt meter.

OSCILLOGRAMS

All oscillograms taken with ground lead of 'Scope connected to receiver chassis andcontrols set for normal reception. Power Booster control adjusted to give 40 voltspeak to peak at cathode of picture tube. Oscilloscope vertical amplifier response wasflat to within 20% at 2 MC.Number appearing to the left of oscillogram specifies setting of horizontal sweepfrequency control on Scope.

6CB61st I.E.MP.

162

(

V4

60862nd LF AMR

VI

6B(6GATED SYNC.SEPARATOR

320

NO

6CB60,5 IF. MP

30

0+

USA

1/212AU7SYNC AMP

VIE RIG

6AU6 1/2618SOUND I F AMP SOUND DISCRIMINATOR

LIMITER SOUND, AMP

120

162

0

67

0

1691116

ITONo6

il2

35

14

06

vOLUME

154


OFF

112,7

V6

128TTNO A.

STEWART - WARNER Models 21T -9700R, 21T-9700RB, 21T -9700W,21T-9700WB, 21T -9700X, 21T-9700XB.

000

AlOAAll1/26SN7G1 1/26SNIGTHORIZ A F C HOW HOCKING

OSCIIAATOR110

-11

i.09 116

r

V11

6A05SOUND OUTPUT

g 21101.

Al

6AU6HEM AGC

LIMB

'/,608AGC CLAMP

- -

VII

6806610HORIZONTAL SCANNING

OUTPUT

tISY

11.. 1I01/

193

662. 662104

BRIGHTNESS

VIZ

18361MGR VOLTAGE

RECTIFIER .

013

6AXAGTHORIZONTAL

DAMPING

WIDTH

1/9B VII

9i12007 6AN4GTVERT BLOCKING VERTICAL SCANNING

OSCILLATOR OUTPUT

209

a'sr, 200

vE Ft§141

297 20s

VIA

21ALP4APICTURE TUBE

N W /OCRS.

.60A

t1,1,41. T LEE,.WAVEFORMS

30

VOCAL/TTFTT'F R1T T M TNT.

CURRENTlflR

e Mon co PPPPP 31611111

FRTIPOve Fgt. OWLVI

e

155

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONSTEWART - WARNER Models 21T -9700R, -RB, -W, -WB, -X, -XB, Continued

6807 OR 6807ARIM/

/OS

BOTTOM VIEW OT CHASSIS SNOWINGCONNECTION TO HI 11.15E0 ONO

OPNMLN JHGFE521068 R.F. TUNER UNIT

(SHOWN WITH SIDE SHIELD REMOVED)506667WIDTH

BLUE -BROWRED -YELLOW 4,001:1

GREEN-}'

..11TERMINAL CONNECTIONS

FORYOKE LEADS

TUBE AND CONTROL LOCATIONS

424 520714- COIL -CHOKE426 520715 COIL -CHOKE

520714 COIL ---CONVERTER PLATE T.F.427--, (INCLUDES SLUG & CLIP)

509062 SLUG CORE -CONVERTER PLATE COIL414 520518 COIL -CHOKE4 16 520520 COIL -CHOKE

.15

.751

.1

.10

-0 ;i5z o z0.

ca

8 E aS-4

COC O 0C.) C.)

5.4

D o -4E.)

PART USTGRAMDESCRIPTIONNOPRICENO.

COILS AND TRANSFORMERS

21___TETTRrs..1S7VrE0 I.F.VC.CIOISeG)T. 1 .2

15030-- 520977 TRANS. 2ND VIDEO I.F. (LESS SLUG) .79

7357 SLUG CORE: 2ND VIDEO I F. COIL .2035___./ .. ::. ii 1. 0 --1. Ore I ./. Iir *I I - .

39 5206.- COIL -PEAKING (SINGLE PI. CODEDPURPLE OR GOLD DOT) .65

41 520984 CO/L-PEAKING (SINGLE PI. CODEDRED DOT) .50

(509601 COIL -4.5 MC. TRAP (INCLUDES SLUG47-- AND CONDENSER 448) 1.20

507357 SLUG CORE: 4.5 MC. TRAP COIL .2049 520689 COIL -PEAKING (SINGLE PI, CODED

PURPLE OR GOLD) .6551 509141 COIL -PEAKING (SINGLE PI. CODED

GREEN DOT)69 5234.5 ION TRAP 1.1072 521267 CENTERING MAGNET ASSEMBLY

(INC. WITH BACK COVER OF YOKE) 1 105 9 951 TRANSFORMER -POWER 17. 02 50 141 CHOKE --FILTER 3.5 507584 COIL --CHOKE .2130__J5225 9 TRANSFORMER--SYNCROGUIDE 1.50

15210.4 SLUG: SYNCROGUIDE TRANSFORMER144 52 417 TRANSFORMER. ORIZONTAL OUTP 6.50146 vs.. o --W # N L LUG & LIP

4.1; ; , i 4' '1 160-A.522987 YOKE. PIX TUBE DEFLECTION

MAGNETB RESISTORS AND CENTERING MAGNET)12.50163 509178 TRANSFORMER --AUDIO TAKE -OFF 1.50168 509706 TRANSFORMER --SOUND DISCRIMINATOR

(INCL. CONDENSERS 168A & 168B) 3.00190 5093/6 TRANSFORMER --AUDIO OUTPUT 1.85194 520980 TRANSFORMER--VERT. BLOCKING OSC. 1.90213 520975 TRANSFORMER--VERT. OUTPUT (INCL.

CONNEC. FOR DEFLEC. YOKE LEADS) 4 00520702 COIL -ANTENNA CH. 2 CODED 20_ 1%0

1.40iga COIL -ANTENNA N: 4 CODED 44 1.40520705 -OIL-ANTENNA CH. 5 CODED 1 405Q520706 COIL -ANTENNA CH. 6 CODED 61Q 1:40

401 52070/ COIL -ANTENNA CH. 7 CODED 70 1.15520705 COIL -ANTENNA CH. 5 CODED 80 1.15520709 COIL -ANTENNA CH. 9 CODED 90 1.15520710 COIL -ANTENNA CH, 10 CODED 109, 1.15520711 COIL -ANTENNA CH. 11 CODED 119 1.15

1 -:, 111 . @OM 1.15! '4 t, '4,),: . ov.10,

406 v v Tv. el' '

520722 'OIL-R.F. & OSC. CH.2 CODED 20 1.:5529723001L-R.F. & OSC. CH.3 CODED 3Q 10;5520724 COIL-R.F. & OSC. CH.4 CODED 4Q 1.I5

T1,735 COIL-R.F. & OSC. CH.5 CODED 59 1.557 6 COIL-R.F. & OSC. CH.6 CODED 6Q 1.85

520727 COIL-R.F. & OSC. my CODED 10 1.70413 520728 "OIL-R.F. & OSC, CH.8 CODED 50, 1.70520729 "OIL-R.F. & OSC. CH.9 CODED 90 1.70520730 COIL-R.F. & OSC. CH.10 CODED 100 1.70520711 COIL -R F & OSC. CH 11 CODED 110 1 70520732 COIL-R.F, & OSC. CH.12.CODED 12Q 1.70520733 COIL-R.F. & OSC. CH.13 CODED 130. 1.70507986 Sum FOR OSC. COIL: AUX. FINE

TUNING ADJUSTMENT .05

156


STROMBERG-CARLSON211-221 SERIES TELEVISION RECEIVER

UHF Conversion Model 21T.In these -node's the receiver is equipped with a tuning

unit that is capable of receiving UHF stations by makinga slight modification on the tuner.

Cautior: U type UHF and VHF strips must be usedin the 21T chassis).

To accomplish Customized Tuning on either UHF orVHF, it may be necessary to center the range of the finetuning control. Set the selector knob to the desiredchannel and adjust the fine tuning control for the mid-point of its rotation. Remove the control knobs andinsert a thin non-metallic screwdriver through the cabinetadjustment hole, and adjust oscillator slug for best pic-ture and sound. Note that each channel is to be adjust-ed individually, both on UHF and VHF.

AGC Adjustment.

The AGC control is located on back of the chassis (Seetube location chart). The purpose of this control is toeliminate an interference beat which may be producedin strong channel 6 areas. The normal position of thiscontrol is fully counterclockwise when beat interferenceis not present.

If this beat occurs, the control should be turned clock-wise from a completely counter -clockwise positior untilthe beat disappears.

T-11 has been changed in production (effective as follows):1. Remove white lead from bottom terminal of trap coil to cathode

of tube.2. Disconnect ground end of cathode resistor (330 ohm] and

by-pass (330 MMF) and connect to cathode of tube.3. Connect jumper, between the ground point of which the

cathode resistor -condenser combination was connected, and thebottom terminal on the same side of the coil.

Keep in mind on the 21-22 series TV receivers that the currentto the IF strip is drawn through V-19 (6W6 audio output tube).Failure of this tube, of course, would remove B plus from the IF

strip, causing no picture and no audio.

The following changes hove been made in production.

1. Delete C-131 .0047 MF capacitor.2. Delete C.133 100 MMF capacitor.3. Delete C-191 .1 MF capacitor.4. Delete R-191 560K resistor.5. Delete R-185 120K ohm resistor.6. Change R-184 from 270K ohm to 560K ohm resistor. (S -C

Part :28188).7. Add 1 680K IA watt resistor R-108 (S -C Part :28189) from

pin 5 of V-19 (6W6 audio output) to junction of R-193 andC-193.

8. Add 470K ohms 1/2 watt resistor R-197 (S -C Part :28187)from R-190 270K ohm resistor to ground.

9. Add 2 6.8K 2 watt resistors R-185 (S -C Part :149053) in

series from B plus 150 volts to ground.10. Remove R-243 3.9K ohm resistor from junction of R-204 and

R-215 and connect to B plus 150 volts.11. Remove B plus 150 volts from 1st IF V-9 (6CB6) at junction

of R-94, R-93, C-94 and connect to B plus 110 volts.

A change in the circuit of the 21-22 series TV receivers to preventpulling at the top of the picture, has been put in production. A

2.2 meg. '/2w. resistor R-249 (S -C Part 5149121) has been addedfrom B plus 310 volts to pin 1 of V-20 (6AU6) keyed AGC tube.A 47K 1/2w resistor R-216 (S C Part ;;149111) is added acrossL-28 horizontal frequency coil. (Code date 54-211).

ALTERNATE TRAP ALIGNMENTIF THIS METHOD IS USED, IT SHOULD BE PERFORMED BEFORE THE IF CURVE ALIGNMENT

SIGNAL GENERATOR OSCILLOSCOPE ORCONNECTION VTVM CONNECTION ADJUSTMENTS

1. Connect a modulated (400 Some as Step ); 1.cycle) 39.75 MC signal to the (above).grid of 1st IF tube, pin 1 ofV-9, 6CB6.

1. Adjust top slug of T-6 forminimum response on scope.

2. Connect a modulated (400 Same as Step /t 1.cycle) 47.25 MC signal to thegrid of 1st IF tube, pin 1 ofV-9, 6CB6.

2. Adjust top slug of T-8 forminimum response on scope.

3. Connect a modulated (400 Same as Step It 1.cycle) 41.25 MC signal to thegrid, pin 1 of V-9, 6CB6.

3. Adjust top slug of T-7 andT-11 for minimum response onscope.

Complete alignment on the page after next. Circuit diagram on the next page, over.

157


Stromberg-Carlson 21T - 22T Series Television Receivers Circuit Diagram

158

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONStromberg-Carlson 21T - 22T Series Television Receivers (Continued)

ALIGNMENT PROCEDURE

Apply AGC bias of approximately 3 volts to AGC line (across C-160).Maintain the output level of the sweep generator to obtain a second detector output of 2 volts peak -to -peak. Oscilloscope should be calibrated to read 1 -VOLT per inch vertical deflection.

SIGNAL GENERATORCONNECTION

OSCILLOSCOPE ORVTVM CONNECTION ADJUSTMENTS

1. Output of 40MC. sweep gener- Input of scope to grid of 1. Adjust the bottom slug of T-7ator to grid of 1st IF tube, pin Video Amp., pin 1 of 1st IF transformer for low inter-1 of V9, 6CB6 thru 100 MMF V-13, 6AU6 thru 47K - mediate frequency (43.2 MCisolating capacitor. Ohm isolating resistor. approx.).

2. Adjust the bottom slug of T-93rd IF transformer for low fre-quency. (42.0 MC approx.).

3. Adjust the bottom slug of T-8

cs) al

c -t3c17) 'al

'I

4.

2nd IF transformer for high fre-quency. (45.0 MC approx.).Adjust the bottom slug of T-104th IF transformer for high in-termediate frequency. (44.5

0 g MC approx.).V 3E 0

-C

E E2

5. Maintaining the above relativefrequency positions of the in-dividual stages, adjust theslugs to produce a curve asshown with the 41.9 and 45.75oc

OC-0tu

at o

ai at-o

H

MC markers at 50% responseFig. 1.

2. Output of 40MC sweep gener-ator to junction of T-6 andL-18. Using 39.75MC marker.

Same as Step g 1. 1. Adjust the top slug of T-6 forresponse 39.75MC as shownon curve Fig. 2.

2 03. Same as Step 2. Same as Step g 1. 1. Adjust the top slug of 1-7 and

Using 41.25MC marker. T-11 for response as shown oncurve Fig. 2.

FIG. 1

Jrj39 7.s -

FIG. 2

4. Same as Step 1 using 47.25 Same as Step 1; 1.MC marker.

Adjust the top slug of T-8 forresponse curve as shown onFig. 3.

2. Repeat Step 1 (IF response)to reproduce the curve asshown in Fig. 1.

FIG. 3

5. Raise converter tube shieldfrom ground and connect out-put of 40 MC sweep generatorto the shield.

Same as Step # 1. 1. Adjust the bottom slug of 1-6and T-5 tuner assembly toproduce a curve as shown inFig. 4.

FIG. 4

6. Connect a 400 cycle modulated4.5 MC signal to the junctionof Video Detector M-13 andC-126. Adjust generator out-put to a level to ihdicate 1.5volts VTVM.

Connect 2-100K resistors 1. Adjust L-21, T-15, and the bot-in series from the plate tom slug of T-16 for maximumof ratio detector, pin 2 indication.of V-18, 6T8 to ground,connect VTVM from junc-tion of the resistors toground.

7. Same as Step 1; 6.

Tube and trimmer locationdiagram on the next page.

Connect VTVM ground 1.Lead to the junction ofthe 2-100K resistors(see step 1$6 above).Connect VTVM D.C. leadto the junction of C-181and R-181.

Adjust the secondary (topslug) of T-16 for zero voltsbetween the positive and nega-tive excursions. (Increase gen-erator output for good deflec-tion).

159


Stromberg-Carlson Tube and Trimmer Location Diagram

21T -22T Series Television Receiver

o BRIGHTNESS R -I52

o HORIZ. HOLD R -25I

0 VERT. HOLD R-223

VOLUMECONTRAST

0R -I44

OSC. TRIMMERADJ. HOLE -V

C-23

MIX.-OSC.

CDC -28

©C -I9

R. F. AMR

C -I5 21T822TV.H.F. TUNER

21 T22 T

LOW FREQ. TRIMMER

U.H.F TUNER221 ONLY

SYNC.

SEPARATOR

VERT. OUTPUT

M-7T- 6

CON V.SEC.&39.75McTRAP

T-7 T

211SIVIDI. F.

TRANS4125 Mc VID. 4725m, 3r-VID.

I.F. AMP TRAP I.F. AMP. TRAP I.F. AMP

[OVID.

TRVS.3r-ci VID.

I. F.

TRANS.

T -I00.1=1 VID.

TRANSa

DET.

AUDIO OUTPUT RADIO DET.

AUDIO AMP.

POWER RECT.

T -2I

POWER

TRANSFORMER

T- t6

0RATIO DET

GND.

214 AUDIOAMP.

FOCUSSOCKET

GNO.

150V. 310V.

41.25 Mc TRAP

L-21

T-15

AUDIO I.F.

SOUND

TAKE OFF

6 AU6

I-- AUDIOI. F. AMP.

KEYED A.G.C.

HORIZ. AMP.

REAR SPKR SOCKET FOR R-258

R-53J I

KINESCOPE °LEADS- -2

VE SIZE@ o) LIN.-232 L-28 R-208

INTERLOCK A.G.0HORIZ. FR EQ CONT. FOR

IOVID.AMP.

SYNC. PHASE INV.a BLOCKING OSC.

L-27 4.5 MC. TRAP

VID. AMP. PHASE DET.

e -t

V-281B3

H.V. RECT.

M-2-II/4 AMP.

250 V.

HORIZ. DRIVE L-30 HORIZ. SIZE

RV__.))NOISE CANC.

-210 CONTR. 0L-29

YELLOW KINESCOPE LEADORIZ. LINE

NOTE: 1N105 Diode Detector is Located Under Removable Shield Cover of T-10 4th Video IF Trans.

161)


SYLVANIA ELECTRIC PRODUCTS INC.

CHASSIS 1-522-1, -2

MODELS 596 SERIES

TOPMOUNTING BRACKET

PINCUSHION CORRECTORMAGNETS

SAFETY GLASS

PICTURE TUBE

MASK-.

HALOLIGHT TUBE

LIGHT SHIELD MOUNTING FASTENER

MOUNTING ROD

BOTTOM MOUNTINGBRACKET PICTURE TUBE SUPPORT

PICTURE TUBE INSTALLATION

YOKE MOUNTING WING FASTENERWING NUT

FOCUS AND CENTERING UNIT

-ION TRAP MAGNET

PICTURE TUBE SOCKET

CENTERING LEVER

FOCUS ADJUSTMENT

GROUND STRAP TO CHASSIS

HORIZONTAL AFC CIRCUIT ADJUSTMENT

1. Tune in a normal air signal and adjust L71 HorizontalSize control for approximately normal scan using alocked -in picture.

2. Turn receiver power "off" and connect shorting jump-ers as follows:

a. From junction of R212 (330 ohm) and 'I 60 sync phasesplitting coil to chassis.

b. Across terminals of L68 Horizontal Frequency coil.

3. Turn receiver power "on" and tune in a normal airsignal.

SERVICE INSTRUCTIONS

REMOVAL AND CALIBRATION OF CHANNEL SELEC-TOR KNOB:

a. To remove Channel Selector knob, loosen (do notremove completely) knob retaining clamp screw.Knob may then be pulled off tuner shaft.

b. To calibrate Channel Selector knob, rotate ChannelIndicator Dial in cabinet front until channel num-ber that tuner is set to appears behind picturewindow glass. Install Channel Selector knob mesh-ing its gears with those of the dial. Make anyminor adjustments required to insure that dialnumber corresponds to tuner setting.

4. Rotate R259 Horizontal Hold control to center position.

5. Adjust R260 Horizontal Range control until picture movesback and forth across screen with blanking bar vertical

6. Remove shorting jumper from L68 Horizontal Frequencycoil.

7. Adjust L68 Horizontal Frequency coil until picture movesback and forth across screen with blanking bar vertirA.

8. Remove shorting jumper from junction of R212 (330 ohm)and T60 sync phase splitting coil to chassis.

KNOB REMOVAL,LOOSENIDO NOT REMOVE)

KNOB RETAINING SCREW

FINE TUNING

FINE TUNINGKNOB

CHANNELSELECTOR

Service material onChassis 1-522-1, -2,continued on the nextfive pages.

161

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1. Standsis

2. Ground3. Keep4. Allow

utes5. Deflection6. Use

allic7. Wrap

(6X8)

PREALIGNMENT INSTRUCTIONSREAD CAREFULLY Sylvania

chassis on side with high voltage shield down for under chas-adjustments. Chassis

all test equipment unless otherwise stated. Models

Electric Products1-522-1, -2

596 Series(Continued)

detector circuit leads as short astest equipment and receiver chassis

after the intial equipment and AGC

possible.to warm up for 15 min-battery setup.

alignment.powdered iron cores. Met-

screw adjustments.around pin 7 prong of V2

test equipment connections.

VIDEO IF ALIGNMENT

yoke should be connected duringnon-metallic alignment tools forscrewdriver may be used for brass

a short length of insulated wiretube in VHF tuner to facilitate

STEP ALIGNMENT SETUP NOTES TEST EQUIPMENT HOOKUP ADJUST

1. Connect 20V. battery (-) terminalto junction of C129 (. 047 mfd. )and R128 (120K) and connect (+)terminal to chassis.

Set VHF turner to signal -free chan-nel with minimum interference.

SIGNAL GENERATOR - to ungrounded tube shield L54 (top core) for MIN. at 39. 75 MC.T55 (top core) for MIN. at 41. 25 MC.L55 for MIN. at 41. 25 MC.T56 (top core) for MIN. at 47. 25 MC.

Use sufficient signal generator out-put for satisfactory VTVM reading.

on Osc. /Mixer tube on VHF tuner.

VTVM - D.C. Probe to junction of L58 peaking coiland R151 (2. 7K).

2. Same as 1. Same as 1. T58 for MAX. at 44.0 MC.T57 for MAX. at 42. 0 MC.T56 (bottom core) for MAX. at 45.2 MC.T55 (bottom core) for MAX. at 43. 2 MC.

Adjust signal generator output to keepVTVM reading between 1 and 2 volts.

3. Repeat step 1 trap adjustments.

4. Remove 20V. AGC battery.

Disconnect T55 lead from pin 5of V3 (6CB6). Connect 330 ohmresistor across T55 primaryfrom R132 (1K) to pin 5 of V3.

Set VHF tuner to signal -freechannel with minimum inter-ference.

SWEEP GENERATOR - to pin 7 of V2 (6X8). Set to43. 5 MC with 10 MC sweep.

SIGNAL GENERATOR - loosely couple to sweepgenerator lead.

OSCILLOSCOPE - through detector circuit to pin 5

L54 (bottom core), L16(VHF tuner) and L53for response curve shown:

L53 L54 (30T.)42.1 MC. 16(TUNER)

45.75 MC.

L54(T'0P)39.75

MC.of V3 (6CB6).

220KO--1.00../ 1N34 :

0., . SCOPEINPUT 120K INcK/- ,001

CRYSTAL

(NOT NECESSARY ,F SHIELDED LEADS USED ON SCOPE1

5. Repeat step 4 adjustments until response curve is flat with 42. 1 MC and 45.75 MC markers

6. Connect 20V. battery (-) terminalto junction of C129 (. 047 mfd.)and R128 (120K) and connect (+)terminal to chassis.

REMOVE 330 OHM RESISTORAND RECONNECT T55.

Set VHF tuner to signal -free chan-nel with minimum interference.

SWEEP GENERATOR - to ungrounded tube shield Retouch T58, T57, T56 (bottom core) andT55 (bottom core) if necessary to obtainresponse curve shown:

45.0 MC. RESPONSE-100%

on Osc. /Mixer tube on VHF tuner. Set to43. 5 MC with 10 MC sweep.

SIGNAL GENERATOR - loosely couple to sweepgenerator lead.

OSCILLOSCOPE - through 33K resistor to junction

PIX42.1 MC. 45.75MC.

SOUND41.25 i SOY, 47.2 5 MC.

of L58 peaking coil and R151 (2.7K).

163


Sylvania Electric Chassis 1-522-1, -2, Alignment Information, Continued

4.5MC TRAP ALIGNMENTSTEP ALIGNMENT SETUP NOTES TEST EQUIPMENT HOOKUP ADJUST

1. Short pin 2 of V6 (6AM8) tochassis.

SIGNAL GENERATOR - to pin 2 of V8 (12BY7).Set to 4.5 MC.

VTVM - R. F. Probe to pin 11 of V24 (Picture

L61 for MINIMUM.

Tube); Ground Lead to chassis.

SOUND ALIGNMENT

STEP ALIGNMENT SETUP NOTES TEST EQUIPMENT HOOKUP ADJUST

1. short pin 1 of V5 (6CB6) to chassis.

DO NOT GROUND VTVM.

SIGNAL GENERATOR #1 - through 1K resistor to T52 (both cores) for MAXIMUM.T59 (both cores) for MAXIMUM.

Use peak resulting in greatestseparation of cores.

Repeat adjustments until max -imum reading is reached.

pin 2 of V6 (6AM8). Set to 45.0 MC.

SIGNAL GENERATOR #2 - through 1K resistor topin 2 of V6 (6AM8). Set to 4. 5 MC.

OR

SIGNAL GENERATOR - through 1K resistor topin 2 of V6 (6AM8). Set to 45.0 MC with acrystal controlled 4. 5 MC marker.

ALSO

VTVM - D. C. Probe to pin 5 of V10 (6AL5); GroundLead to pin 7 of V10 (6AL5).

2. Same as 1. USE SAME SIGNAL GENERATOR HOOKUP AS INSTEP 1.

VTVM - D.C. Probe through 100K resistor to term-

T52 (top core) for ZERO.

Use lowest VTVM scale set tozero center. At correct coresetting, a slight turn of corewill give either a positive ornegative reading.

inal #1 of de -emphasis plate; Ground Lead tojunction of two matched 100K resistors con-nected in series across R106 (68K).

3. Remove test equipment and resistors; then, tune in a weak station and adjust T52 (top core) for optimum signal-to-noise ratio.

ALTERNATE SOUND ALIGNMENTSTEP ALIGNMENT SETUP NOTES TEST EQUIPMENT HOOKUP ADJUST

1. Connect a good antenna instal-lation to receiver.

Set VHF tuner to a strong sta-tion.

DO NOT GROUND VTVM.

VTVM - D. C. Probe to pin 5 of V10 (6AL5); Ground

T52 (both cores) for MAXIMUM.T59 (both cores) for MAXIMUM.

Use peak resulting in greatest separationof cores.

Repeat adjustments until maximumreading is reached.

Lead to pin 7 of V10 (6AL5).

2. Same as 1. VTVM - D.C. Probe through 100K resistor to term- T52 (top core) for ZERO.

Use lowest VTVM scale set tozero center. At correct coresetting, a slight turn of corewill give either a positive ornegative reading.

inal #1 of de -emphasis plate; Ground Lead tojunction of two matched 100K resistors con-nected in series across R106 (68K).

3. Remove test equipment and resistors; then, tune in a weak station and adjust T52 (top core for optimum signal-to-noise ratio....

164

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONSylvania Electric ProductsChassis 1-522-1, -2

(Continued)

HOLDR220

AC INTERLOCK

VERTLINEARITY

R227

HEIGHTR225

PICTURE(CONTRAST}

R152

HORIZ.RANGER260

NOR SCAN a H VCONNECTORSOCKET

HORIZ.HOLDR259

V235U4 GL.V RECT0.300V

T50POWER TRANSFORMER

V225U40

L.v RECT.(1140v)

V1661116 GT

VE PT.OUTPUT

VERT OSC.

SYNC. AMP. aCLIPPER & AGC AMP

L7iHOR SIZE

L I

14.SMCTRAP)

12BY7

VIDEO AMP

NOR. PHASE DET NOISE INVERTER

VI96 GD6G

HOROUTPUT

0259

1B 3GTH V

RECT.

V3B6

I STVIDEOIF AMP

vo6G 136

2ND VIDEOIF AMP

SOUND a SYNC. AMP SYNC SEP

V206AU4GTDAMPER

RATIO SET

VIP

6SN7G TA

NOR071

L68(HOP. FRED.

COIL )

1ST AF AMP, TUNERAGC CLAMP a ATC DIODE

VI2

6V6G TAFTPUT

CHASSIS TOP PARTS LAYOUT165

ON/OFFSWITCH'.

VOLUMER104T53

AUDIO OUTPUTTRANSFORMER

HALOLIGHT

SOCKET

C I 491


0C115

Sylvania Electric ProductsChassis 1-522-1, -2

(Continued)

CHASSIS BOTTOM PARTS LAYOUT

ITT

OW nwav N

0131

0133

RI30

c)

ev.0

R130

C135

C136

OTt33

v46086

8137

onoco Il=RI39

C2I1R2I6

RI 2 0127RI31

179

6128

8132 1 J,RCl30 T50RI29 POWER

TRANSFORMER0132

81346127

0 Rt26

SW Jo

1786136

RI25

L51

1k11 RIR143

trP WS .Z" ,RI4238

0137

R159

ON/OFFSWITCH

6104VOLUME

CONNECTOR

DE-EMPHASS1SPLATE

C1010102,C103,R102

CIO/2

8105

CI08

0

O00

153AUDIO

OUTPUT

RH!

8103

C1008100

R01 09

101

A

A

gor* 111

V9

6AU6

B

R

261

02530253

C 1

V66 AMI3

G142

CI46RI48

I

44

8146tC14 3

T0

L56

SHIELD

R204

RI49

R206

104

R 2

4m

0202

RI58

V186SN7GT

R259

R256

R2028203 0145

8207

C203 R20C200

0251

C20

1-5°

FILTERCHOKE

LV

8258

0134

121

0177

129

C126

RI24

RI20144

76

SHIELD

44R150

q0 216

A

L57, L56

0147

RI57C207

R153 L59,L60C148

IIIRI54R147 160

G205

R1561%PqeRI5 44IR2 2

R250-r , R254

3

11111 252

L7

AW1**9)

V206AUIGT

8205

R263

.4--

R228

nil.RI75

R176VI 6

6 MGT

2269

217

0214

C 210

mR221

R226222R214

8215

206

IIV

212

8209 0261

R206

255

0256

0262

R160

R264

0208

8210

,R211

R2I3

0204

C250

V196 0066

69

8220VERTHOLD

AC INTERLOCK

- 2271VERTLIP.

R225HE4

RI52CONTRAST

7260

RANGE,

N. V CONNECTORSOCKET

R259NOR

HOLD

166


TRAY-LER RADIO CORPORATION

Chassis Nos. 48A3 and 48A4The material on pages 167 through 170 is exact for chassis listed above.Chassis 47A3 is the same except a different tuner is used.Chassis 48C4 is very similar to these models.Chassis 49A4 is almost the same, but uses still another type tuner.The alignment information applies to all these chassis.

FRONT PANEL CONTROLS

U.H.F. DECADE SELECTORPICTURE FINE TUNING SHAFT

HORIZONTAL VERTICAL BRIGHTNESSOFF -SOUND HOLD HOLD

V.H.F. SELECTOR BU.H.F UNIT SELECTOR

FIGURE -I

ALIGNMENT INFORMATION

The 40 Mc IF amplifier strip can be aligned by following the procedure listedbelow. These instructions are to be used in conjunction with schematic diagram

These IF transformers use a threaded coil form with a powdered iron corehaving a 3/16" hex center and is to be adjusted with a non-metallic alignmenttool with a 3/16" hex stud. One such item is the Walsco 2526 molded -nylon tool.

1. Tune receiver to channel 12.2. Set PICTURE control fully counter -clockwise (minimum).3. Connect negative lead of 3 -volt battery at point (B) shown on

schematic diagram; connect positive lead to chassis.4. Connect vertical input of oscilloscope at point (A); connect

ground lead to chassis.5. Connect sweep generator (40 to 48 Mc) to loosely coupled shield of

6J6 or 6U8 oscillator -mixer tube making certain that shield is notgrounded. Connect ground lead to chassis.

6. Connect synchronized sweep voltage from sweep signal generator tohorizontal input of oscilloscope for horizontal deflection.

7. Marker generator frequencies are 41.25 Mc for sound carrier and 45.75Mc for video carrier.

8, Adjust IF coils and transformers L-6. L-47, L-49. IJ-48. and L-50 forresponse curve similar to figure below with markers as shown,

9, L-6 Mixer plate coil of tuner tuned near center of pass band atapproximately 43.5 Mc. Detuning affects dip at bottom of response curve.

10. L-47 IF input coil tuned near center of passband at approximately 44.5Mc. Detuning affects dip at bottom of response curve.

11. L-49 (bottom) 1st IF transformer tuned to low side of pass band atapproximately 42.5 Mc. Detuning affects low side of response curve.Sound carrier trap coil (top) tuned to 41.25 Mc.

12. L-48 (bottom) 2nd IF transformer tuned to high side of passband atapproximately 45.5 Mc. Detuning affects high side of response curve.Adjacent channel sound carrier trap (top) tuned to 47.25 Mc.

13, L-50 3rd IF transformer tuned to center of passband at approximately44 Mc. Detuning tilts bottom of response curve.

167

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONU.H.FANT

ST)O-n-

10

L-1

C-32

V.RFANT. # 300

JL 5

L-15

C-14 C-I5c68

L -I6

R-4.70t.

L -I2

/ROT RIL-3

1

_L

IL 1

L_U.H FOSC ADUST.

VT -16BZ7

D:16 -1L-21

0-175-3

_--

IC -18 7n-5

3.,

IZOK L-20 15 --i-_-47.2 L-23

--'-- 'Ft,S91 R-9

5 FS15K

C-510_31I

680 1R-8.0

0-2047

VT -26U8

2

R-10

R-I51100K

51C -I054 220 L_

2 1

r R-3 8 4 5 L-24 _-

C -I00INE

II } 226 It .._1,c lipyi -F

I I N31

I 145-3j_

I

-.....___,C12

2 1 TUN

L7-19I ...i-/-

C-II C-10 1 .C -I04

R36

6.81 S-3 1- - 11_1 R -II=Cii1)03

10K I

R-2 ?" R-12 = R -I347K _L --',-09

-_-_- -ww-4-vom_ 536L -9

33K1300

0107ee

eC

6

.-_-

R-1711.26

C-610

1N82

R.FCOUPLING

IC-5

JL-5 115e

r r

TUNING

R-110K

VT -66AF4

L_ =

11

100.09 R411;

67

U.H.F OUTPUTPLUG SOCKET ;

S 30-R-7 5

IK

L-26

C-7 4 L-27 1

36261 t

41171 C PRE -TtNIP COILSS.tched m 1%a U.H F

NC150100

L.S

TUNERTERMINAL.

STRIP

C -I100--j1500

-1---=-

OUTPUTPLUG KSOCKET

RU IP(AKCIN

EC -17IOU,4104

R -F7

ow

L- 47

L

VT -116V 6GT

C {8&Goo

V

R-66EEO

IV/

C100-201

C.61I -

05W

I4-6570K

R-104

PLUG BTV -TA -11 TUNER SOCKET _J

TUNER SHOWN IN V RE POSITION

CAPACITORS ARE SHOWN IN 511CR0 MICRO FARADS UNLESS

OTHERWISE SPECIFIED.

RESISTORS AR: 1/2 W. CARBON UNLESS OTHERWISE SPECIFIED.

POW('TRA1310117CI

LPL &win .4 ON00 LUtat CO:07406

/ 2 "AI SLOOLO

CABINETFUSE

C-101

5000

IC -102INTERLOCK I - woo

8-100220K

6.3v VT -201 5U4 G

Sv

4C V

4 30X

6.3V

LINE VOLTAGE II7V.AC. ALL VOLTAGES D.C.2.ALL VOLTAGES MEASURED TO CHASSIS AND ARE' POSITIVE

UNLESS OTHERWISE SPECIFIED.3.VOLTAOE READINGS TAKEN WITH ZERO SIGNAL INPUT

AND PICTURE CONTROL SET MAX. CLOCKWISE.ALL OTHER CONTROLS SET FOR NORMALOPERATION.

4. VOLTAGE READINGS TAXEN WITH ANELECTnONIC VOLTMETER

C Woe(MGR!!

EC -1640 r.r

R-18 R-19

2200 680068001W SW

1000 U F HOINIONTAL

c -ii wKE

7

R-10310K 10

Si070Fes

18001

WIDTH 108 47

R-115

HIS

EC -25A1;0141

4S0 50 v30 Ur-

+. S.ruSE

4 A UP

C 98

600v

0ID

C-97uf =

*000

VT -196W4GT

R-102 C-9315000

IC-94SOO

2080

C-95IUF

C-9603L1

HORIZ. LIN.

FEED THRU CAPACITORS 800uuF EACH

VT -36CB6

VT -46C B6

VT- 56CB6

A

I

C-33 T C-34 T C-35= 1000 = 1000 = 1000

*47 PANEL LAMP

-1-

HEATER CHOKE DETAIL

168


L-49F

s

ii

1-48

VT -3 1 VT -4 VT -56CB6 I

1 6CB6 6CB6135v I 1

-.F I I35V

5 5

7 I35 V.6

1

1

,c,

.I I635VI - 7

--Is--.96I.9Vi

2 6 02I 13V 2

R-24 R -2I47 R-25

47C-21000= -.-

-2370

150C-22 R -2

C0 -32 1 000470 10

1144knoit

25u0

140 7114.1,061.

7

ic-26I .1 uf.

TRAV-LER Chassis 48A3 and 48A4 Circuit Diagram

135V

1

6 mooC-27

135V

I

C-281000

IN64L-50 R-28

100 uh I 5600

C-36 C-29 C-3768 -4 7 3.0

I

R-27470

C-3025u.1

VT -76AH6

2

5

7v

R-29 R-30 R-41ME,-; 470K 47

4

275VcAcr-r-er<)D

4" R-44.-"" L-41 1 ssv6135\' -5.10,-ILO4001

0.4

VERTICAL OUTPUTT RAM11701414ER 654

370v

VC -26

2.561vcort HEIGHT

140V

C-781

R-101leg IW

asusC-76

C-31

12511F

L-17

1000

VC -43APICTURE

CONTROL2

L -32AR-46

R-454700

A

R-47

RAKR4TNESS

1008 2206VC -32 R-49

2106 6AU6

23

iR-5811K2w

C-51SCOO

C-506000

3

130V

166.

a

R-57M

15000

C-47

220 470 KI

C-46

C-441 R-55

11.0 0A,F.

1

e48 - 2V7

R-541156

L2M

L-16

C-49 EC 25BItowj R-85

5600

VIIRT1CAL CC -26

VT -I5 VT -14 SLOCK440 OWL LA/C0nwspoma. 1479A R-798 R 79c

VERTICAL0.141:4417 v

QV

111V C-80=.23ur

EC -21.1407

,-7.4 3 4006430236 vg

220

R-71

0C4 'Loy

- 47°D

6 C'8R.74

VC -39

nosin'CALtr.

VT -176606GT

C-775

R-96 470

v. 100

P-98 R-9547 470KIW

1401Rev(

TC-It

IC -

470

VT -I66SN7GT

R-94 ii5Vwoo C 81

38Q-13v

R-93 *OK15" R-92

1401MITLI

R-75

C-84 7ur R-76

4c4v 2200.

30V

1/2 VT -I31/2 6SN7GT

1200 8200 2214

A C-878 C -87C

C-89=2200

vT-126C41 2.37

NA -WW-R-504711

680K

R-54

3406

R-48100K

R-53470K

>00

C-45x.2 011.L

R -840V

R-83

2700

83-021../F

46 C.yitZt1 iR 91 ssoO

SOO

81171.

R-90Ssoo

L-31 L-16.8

1/2 VT -131/2 6SN7GT

5

R-80

10014

V 4

R-88 68133K

100AA A

C 86 C-88L.18 2so R 82Itsur

1005

C-91 R-87 R-86

0.01 kt,s,fC-901 .

I s4 .0 1llf33.

4700

REAR PANEL CONTROLS

.C. CONNECTORVERTICAL

HEIGHTTYPE 3AG

2 AMPSLO-8L0

FUSEVERTICALLINEARITY

TYPE 3AG

HORIZONTAL HORIZONTAL HORIZONTAL WIDTH1/4 AMP.

LINEARITY CONTROL FUSEFREQUENCY DRIVE

169


TRAV-LER ALIGNMENT INFORMATION (Continued)

41.25 McL-49 Trap

42.25 Mc

47.25 McL-48 Trap

t47.75/ Video Carrier

Dip 10%FIG. 7. Audio Response Cure*

--- TO RECEIVERR ANT TERMINALS

SIGNAL GENERATOROUTPUT CABLE.

R150 OHM LESS ONE HALF THEOUTPUT IMPEDANCE OF SIGNALGENERATOR

FIG. 4. Dummy Antenna Detail

42,7O Mc

TO TEST TO DC PROBEPOINT OF VTVM.)

1000 MAW. 100.000 f

IN34OR EQUAL

TO CHASSIS COMMON

FIG. 5. Diode Detector Detail

SOUND IF AMP ALIGNMENT USING AM SIGNAL GENERATOR AND VTVM

DUMMYANTENNA

SIGNALGENERATORCOUPLING

SIGNALGENERATORFREQUENCY

CHANNEL CONNECTVTVM

ADJUST REMARKS

DirectHigh side topoint (A).Low side to

chassis.

4.5 Mc(Unmod .)

Any channelunusedlocally.

Dc probe topoint (C).Common to

chassis.

L -16Aand bottomadjustmentof L-17.

Adjust for max. voltage at VTVM.

as sa is IIDC probe topoint (E).Common to

chassis.

Adjust topslug of L-17.

Adjust for zero voltage. A positive andnegative reading will be obtained oneither side of the correct setting.

CHECK ON SOUND IF AMP ALIGNMENT USING FM SIGNAL GENERATOR AND OSCILLOSCOPEConnect the ynchronized sweep voltage from the signal generator to the horizontal input of the oscilloscope for horizontal deflection.

DUMMYANTENNA

SWEEPGENERATORCOUPLING

SWEEP 1 MARKERGENERATOR GENERATORFREQUENCY . FREQUENCY

CHANNEL CONNECT ADJUSTSCOPE

REMARKS

Direct High side topoint (A).Low side to

chassis.

4.5 Mc 4.45 Mc(500 Kc .1.5 Mcsweep) 4.55 Mc

Anychannelunusedlocally.

Verticalamplifierinput to

point (C).Common to

chassis.

L-17Touch up the adjustments of L-17 main -taining max. amplitude while adjustingfor max. steei,ncss and straightness ofthe slope. See Fig. 7. Note that the 4.5Mc marker pip tends to disappear asthe correct setting of the top adjustmentof L-17 is reached.


DUMMYANTENNA

SIGNALGENERATORCOUPLING

SIGNALGENERATORFREQUENCY

CHANNEL CONNECT ADJUSTVTVM

REMARKS

Direct High side topoint (A).Low side to

chassis.

4.5 Mc(Unmod.)

Any channelunusedlocally.

AC probe tocathode of

picture tube.Test point (D).

Common tochassis.

L- 16B Adjust for minimum voltage. A crystaldetector shown in Fig. 5 may be usedwith the VTVM in place of a com-mercial AC probe if desired.

170


WestinghouseCHASSIS ASSEMBLY V-2313 AND Y-2323

CHASSIS ASSEMBLIES V-2313-15, V-2313-25, and V-2313-35

Several different variations of the V-2313 chassis are used in current production. The differences willbe found in the type of CRT used and the mounting bracket of the off -on -volume control.

CHASSIS ASSEMBLIES V-2323-101, V-2323-201, and V-2323-301

When the letter "U"appears in the model number, it indicates thar the receiver contains a type V-2323chassis. The V-2323 chassis is identical to the V-2313 chassis with the exception that an all -channelVHF -UHF combination tuner has been factory installed to provide UHF reception of the UHF televisionchannels (14 through 83) in addition to the VHF channels (2 through 13).

Several different variations of the V-2323 chassis are used in current production. The differences willbe found in the VHF -UHF tuner combinations, the type of CRT used and the mounting bracket of theoff-on-volume control. The dash numbers following the basic chassis number identifies these variations.

Models H-838K21B, H -841T21, H -842T21, H -843K21, H -844K21, H -847K21,H -848K21, H -861T21, H -862T21, H -863T21, H -864T21, H -865T21, H -866T21,H -867T21, H -868T21, H -871T21, and H -872T21.Models with same numbers having letters KU in place of K and TU in place ofT, contain a built-in all channel VHF -UHF combination RF tuner.

CHASSIS ASSEMBLY V-2314 OR V-2324CHASSIS ASSEMBLIES V-2314-15 AND V-2314-25

Several different variations of the V-2314 chassis are used in current production. The differences willbe found in the type of RF tuner and CRT used.

Models H -853K24, H -854K24, H -869K24, H -870K24, H -875T24, -A, H-876T24,H -877T24, H -878K24, and H -881K24.

Models with same numbers having letters KU in place of K, and TU in place ofT, contain a built-in all channel VHF -UHF combination RF tuner.

All the sets listed on this page are similar in most respects. The alignmentinformation on pages 172 and 173 is applicable to all sets. Since there area number of important circuit differences between the two groups of chassis,the circuit diagram for Chassis V-2313 (and V-2323) is printed on pages 174-175, while the circuit for Chassis V-2314 (and V-2324) is on pages 176-177.Figure 6, top view of each type of chassis, is printed on page 178, and willaid you in locating tubes and alignment adjustments.

CRITICAL LEAD DRESS

All leads that can result in interaction between stages due to RF pick-up must be dressedclose to the chassis. Leads in this category include the heater, AGC and B4 leads, these leadsmust be long enough to permit dressing close to the chassis.

All leads located near the horizontal multivibrator trimmer capacitor, C421, must be dressedaway from the capacitor and close to the chassis.

Video peaking coils should be dressed away from the chassis and clear of adjacent parts.

The lead-in from the antenna terminals tt) the tuner must be dressed away from the IF stripto prevent "RF" tweet from interfering with the picture.

171

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONWESTINGHOUSE Chassis V-2313, V-2314, V-2323, V-2324, (Continued)

ION TRAP MAGNET

It is extremely important that the ion trap mag-net be correctly adjusted immediately after the setis first turned on during installation. This is trueeven through the set appears to be operating satis-factorily. When the magnet is not correctly oriented,the electron beam strikes the edge of the aperturein the anode top disc instead of moving cleanlythrough the hole. The resultant heat vaporizes themetal of the disc, thus releasing gas which has aharmful effect on the tube. Some of the vaporizedmaterial may he deposited on the screen of the tubeand be apparent as darkened area. An excessivelyhigh setting of the brightness control will aggra-vate this condition. From this it is apparent thatthe brightness control should never be turned up tocompensate for an incorrectly adjusted ion trapmagnet. The tube can be ruined in a very short timeunder this condition.

To adjust the ion trap magnet, position themagnet approximately as shown in Fig. 1. with thecolor code mark facing upward, than rotate the mag-net and move it forward and backward until theposition is found where the picture is brightest. If

the brightness peaks at two positions of the magnet,the position nearer the base of the tube is the cor-rect one. Never more the ion trap magnet to removea shadow from the raster if the brightness is de-creased by so doing. Shadows should be removedby adjusting the position of the deflection yoke.The ion trap magnet must always be adjusted formaximum picture brightness.

WIDTH AND HORIZONTAL LINEARITY

The width adjustment on the back of the chassiscontrols the overall width of the picture, and thehorizontal linearity adjustment controls the rela-tionship between the horizontal dimensions of theleft and the right sections of the picture. A balancebetween the two controls is necessary to make thepicture symmetrical with correct horizontal dimen-sions. These controls are sliding type adjustments.

C RT CUSHION

DEFLECTION TORE API --

UP G DORM CASTER

ION TRAP MAGNET

- AOUADAG GROUNDING SPRING

FRONT, BACK 8 LATERAL CUSTOM MT

jCENTERING MAGNETS ADA

Fig. 1 CRT Adjustments

HEIGHT AND VERTICAL LINEARITY

The height adjustment on the back of the chas-sis controls the overall height of the picture, andthe vertical linearity adjustment controls the rela-tionship between the vertical dimensions of theupper and the lower sections of the picture. A bal-ance between the two controls is necessary to makethe picture symmetrical and fill the mask vertically.

VERTICAL HOLD

The vertical synchronization is controlled bythe vertical hold adjustment. To adjust, rotate thecontrol clockwise or counterclockwise until the pic-ture is stabilized vertically. The adjustment shouldpreferably be made on the weakest signal that isavailable, and a check should be made to see thatthe receiver pulls into sync on all channels.

HORIZONTAL RINGING COIL

The horizontal ringing coil (L400) should be ad-justed as follows:

1. Short out the ringing coil with a short jumperwire.

2. Set the horizontal hold control to the middleof its range, and leave it in this position during thesteps that follow.

3. Connect a VTVM to the pin #2 grid circuitof the horizontal multivibrator, so as to measure theDC voltage between this point and ground.

4. With the receiver tuned to a TV station, ad-just C421 (located on the rear of the chassis) forzero voltage on the meter. If zero voltage can beapproached but not quite reached at one extreme ofthe C421 adjustment, it may he necessary to set thehorizontal hold control slightly to one side of mid -position to obtain zero voltage.

5. Remove the jumper from across the ringingcoil.

(. Adjust the ringing coil for zero voltage onthe meter, and check the adjustment by switching toanother channel and then back again. The receivershould pull into horizontal synchronization on allchannels.

CAPACITOR470 MMFI--11

CHASSIS J ICE,: TESTGROUND Pc1NT

RESISTOR47K

OSCILLOSCOPE

-')

Fig. 2. Oscilloscope Connections

TO SWEEPGENERATOR

172


Westinghouse Chassis V-2313, 2314, etc. Alignment Charts, (Continued)

GENERAL INFORMATION ALIGNMENT TOOL

The chassis and test equipment should be bonded To adjust the slugs in the common I -F trans -together by short lengths of heavy braided copper formers a special tool is required. This tool must fitribbon, and all interconnecting leads should be shield- into the .035" x .093" slot in the slug. An incorrectly

ed and should be as short as possible consistent with designed tool will cause chipping of the slug. A

ease in making connections. suitable tool is stocked under Westinghouse partnumber V-8345.

COMMON I -F SECTION

Rotate the channel selector to channel 13.

Connect the oscilloscope to the video test terminal, point "I3' (V-2314 Aschematic diagram) through the decoupling network shown in Fig. 2.

Correct 9 bias battery AGC line, 'A"a volt to the point on (V-2314 sche-matic diagram).

Couple the marker generator output to the sweep generator output. In thesteps that follow, use the marker to check the response curve at the frequenciesindicated on Fig. 4. B

StepAlignment

Signal Remarks Adjustments1

1. Remove the RF amplifier tube.

2. 44 mc. sweep to 3rdIF grid

Connect detuning clipsto 1st & 2nd IF plates.

Pri. of T302 for max. re -sponse and sec. of T302 Ci

for symmetrical curveshown in Fig. 4A.

3. 47.25 mc. amplitude Use sufficient signal L302 for min. response L. .

modulated to 1stIF grid

to produce sine waveresponse on oscillo-scope.

41.25Nt 4 3.0Mc

422514c 4445.0hic; 41.26MC

OW 45.75kk

4. 44 mc. sweep to Connect detuning clip Pri. of T301 for max. re -2nd IF grid to 1st IF plate sponse and sec. of T301

for symmetrical curve shownin Fig. 4B.

5. 44 mc. sweep to1st IF grid

Detune L103 beforeadjusting T300

Pri. of 1300 for max. re -sponse and sec. of T300for symmetrical curve

6. 44 mc. sweep to1st IF

L103 for 'suck -out' at44 mc. (center of curve),gridSee Fig. 4C. 47.25Mc , 45.0Mc 4 3 OP& 41.25Mc

7.45.7514c 44 OW 42 25tAc

Replace the RF amplifier tube

8. 213 mc. sweep toantenna terminalsthrough network.

Fine tuning set to mid-range

L300 for symmetrical curve Fig. 4. Response Curvesand L301 for min. 41.25 mc.marker amplitude. 'See Fig. at Various Stages of4D. Alignment

SOUND I -F SECTION AND 4.5 MC. TRAP

Connect the signal generator to the video test terminal (point "B" ) through a .001 mfd. capacitor.

StepSignal Generator

Frequency VTVM Connections Remarks Adjustments

1. 4.5 mc. unmodulated RF probe to point "C"(see V-2314 schematic diagram)and common lead to chassis.

Use strong signal from gen-orator

L303 for minimum voltage

2. 4.5 mc. FM Across volume control7.5 kc. Dev.

Use strong signal from gen-orator

L202 for maximum output

3. Same as step 2 Same as step 2 Use weakest signal fromgenerator.

L200, L201 and L202 formaximum output

4. 4.5 mc. AM Same as step 230% Mod.

Start with weak signal in-crease as adjustment ismade.

Quieting control for dip tozero.

173


WESTINGHOUSE Chassis V-2313 and V-2323 Circuit Diagram

2 .t- :o

H

pIO3 oac%cp °

I+CC 000-

>If/ 0

In models using chassis assemblies V-2323-101, V-2323-201 and V-2323-301 a combination VHF -UHFall channel tuner, Part No. V-14130-1 is used.

+

I )1, .4..... 1...ti m+'tEl 0 0 Vg. 2 V w V

Ja al BD4

cb "i a) 1""

iou: ° .1

V, V g ,-Tr . S a>

in 8 - in vre Irs

2 . a. Ee oa 0 t0 1. t1 NC3' a" S :4

g0 u o ...

tesa -o *.d

.o 1 " -

0....N tj aP 7' trs :: A

.,ON os Cs!

IA .0 TJ ff. 2 Eaa'6' E 0 cr-' V 0 o..0 ,t, , r.

bo E st ":1 lo

>.o 0 r -8 0

1 e a: IR gww 0

0 /O.4) *--'>, Ma\ .04j > 0 R.....

ulD CS V-5o 2 1 3' 1

...I

(.1 "pi E.._ ..,

cd 1:0 0 X 00 . pp 4.re ej 0sr V .!.,0 .t' or 0 00 o a z 0 ,,, 7:i a U

1-4 -1 .,a

. /.., 1.. .., > a. r,,...; a....- - E T. 'I, 73 ,-,o -.>, 0 E cs: B co n. Z.

2Lon.

SECTION I R -F

A

IRON CORE

CNANNELS 2 THRo

DRUMSEGMENT

11.100

L1000

ROO220

6SZ7 F AMP

DRUM SEGMENT

RION4709

SIM I ? I Lice.eige, 9 I A0J.COUR

'S LOOP

ng{0000

c ics Cr C1401 f.

Girl3-9

P4V

6827

loco LIDloco s soo 7

0127.005

EIL

I(

RIIIIA

"

TUNER RUM COPE NO. IONALL CAPACITOR VALUES IN TUNER GIVEIV IN MMF. -15,-25 TUNER

6.3VAL

6A)1" 12AT1, _011_61_ 12_8(7 &AI&DAMPER STNC CONTROL FM.DET. VIDEO AMP SOUND IF

SYNC AMP

7/411 4 4 5 irj, 3/L.L5055-

63VAL-0

6SN7GT 126H7 SEE Note/PERT. MULTI. VERSECTOUTPU1PPETR CRT.

lAgl 5 I

inos

6AU6SYNC. SEP

663666AU6 6AL5 w raffiji

630661 METED ACC IORIZ AFC. PILOT LAMP HORIZ MULTINOME OUTPUT

`881

6BK5 6CB6AUDIO OUTPUT 1ST IE

L501 1.502m.U

6 3 44 4 S

60662ND LE

C5 05NIS

T500v.

POWER TRANS.

II1V 7,,?,04 _1_,,5,. iiA- C

= T' 0,-._____.SW 500OFF - ON

seoCIDIF

063 VAL

6CB63RD IF

3)_.1.503I NW

Cero'I= HJI

L50025 V 243V

[sow

5U4G RECT

NOTES:

I. VOLTAGE ROLL VARY WITH CONTROL. SET TING.A *CRAFTING CONTROL. PICTEIRE. 1.7 I vERT.HOLD CONTROL,ft PERT. LIN. cowrie...

2. Km -TO -PEA. wavEFORmS WERE TAKEN WITH THE PICTURE CONTROL SET FOR SIGINAL OF 60V AT THE CATHODE OF CRTALL OTHER CONTROLS SET FOR NORMAL PICTURE

3. PARTS TOLERANCE AND RESPONSE OF TEST MOMENT MAY CAUSE SOME VARIATIONS OF THE PIM -TO-PEAR VOLTAGE READINGS.A. 0-C VOLTAGES MEASURE FROM CHASSIS GROUND USING A 20.000 OHM/VOLT METER AND NC SIGNAL INPUT READING SHOULD NE

AS SHOWN! 20 PER CENT.S. ALL CAPACITANCE vALUES IN MFD. AND ALL RESISTANCE VALUES IN OHMS uNLESS_OTNERWESE SFECIFIED.6. WATTAGE RATING OF ALL Vt WATT RESISTORS IS NOT SPECIFIED, OTHERS S oNDICATED.

2IVPI IN Al CHASSIS ZIWMA IALUMINIZED) IH E CHASSIS.

7W

21ST

R4543

SECTION 5 POWER and HEATERS

174


WestinghouseChassis V-2313 and V-2323 Circuit Diagram

In later production of the V-2213 or V-2323chassis the horizontal output tube has been re-placed by a 6BQ6GA or 6CU6 tube. Both tubes aredirectly interchangeable.

1 4, WC:1- AMP.

1. 200

C200,

1106C203

47MMF

0203 g35061,

8201L26

C207T-005

SECTION 2 SOUND I- F and AUDIO

031_46' IA OLT 8203.t75,470

C205 71777 is

12°1--00,

520,13$

11205Q UIETING t 22KCONTROL 2W

6223124

T;c:"-j-C211'158207

6BK5AUDIO OUTPUT

1031

C218206 6

.05006 5209vOLUMET 801 ""C213BCONTROL _ 30

-C215=.005

16210°TaftTRANS.

1.1-M

6C6611, 17 AMP 1300

1206 -10

4.300 I' #300 I a,0 7

2.2N,

:M

00 i 3 303

I ?-1- 11Ar6B

If3325

1.5/4

42:1"--i 0322ISM T .05

R32775004G.C.

CONTROL

R3263903

-0324I .005

830168

11330113K

R3034,10

C3600

4, 63291000

302470

A31:?C 0306MF 2.2

um,1.3

#00

TRIL PT/P P 60

3047

C3246714146

6CB6292 IF AMP

301156r -41 odo II

ID 12

2

R30468.

C 308 I-4%305

4

8315Care 3.9002 2 SW

606 r - TRTstiZi - - ---I 12802 0 L30113 ED IF AMR ,

1 0309 1/1020 .40P. L306 1.30783 290.C6706-11164 1997 win IvuukorMy I 22° # lecnoroc,v Oro

5 4100 i a *I rnr \ 1 21.^..."--1. L 3 0 5 T -12 6

t..t.,?2,0241'

-"I': Bus" C31756 8226

R381OM

1.5V

CfK41

470YMF

10 5091.005

ISV

T

30o

11i301-1470

1056L 306

MDEO-C311 TEST

9°C/4517

PONT

4.

SECTION 3 VIDEO

310336

4.18338

R312 1

10

11211 8313120 L50

PICTURECONTROL

1306

60 V P.P80".,

C321 -.1

1.320006

634N0)06

I 2526

CO N8111121121.666

TROL

FOCUS 8321CONTROL 216

8516120V

C436#1+" I- 258SW0448

1Y 3308

1106

C435

6AU6KEYED AGC

5

1306

#4492206

R27

40006

5V

2

R4524.7iW

0453

214

2 AT 7SYNC CONTROL

SYNC AW.

R4024.711

200 P 60,,006

. 510C SE P.840121 0 270 MAW

C400 R404 r2.01 4700

R405

4510.16

3867

704

6

1/2 12 811

11015E CLIPPER

C4742V

R450

6405

5501/

718

46

r3.9.0.6

130

54 P 60, .45 v P -P 60,0406 --476

6 376

0402270

7400

R" IAI -226

403 398 I I .002 .005T

=I

R4I1100K

I VI

BOV

6521119.LT_050 T. mull,. 11100ILP 60,

166 MP606,

62.1.5

60/114 2, 45.,.

0426

850 P -P 13.750C412

150 811101N4L

40

056 COIL

C009 C3908

51616 MAK

I-19-18425

119

33 6 P.P 15,756 5.C 413i 660 Tm,

R42/2206

8438

2445'.005

II

R429566I.

0431

Cole5900 1200 PP 15,750 6.,MMT

110612. 'AULT . /60l2AU7

6 etrlij

C414 8426 470 2

3.26.01 I 47060440

01 60kR434

18 V 15,75 7576'.1..0°.°

11447 11

8436,560

0421

560

200V

2.1116

R442 1C405

L265

F4001/4 AMP2500

C4T96.:110

R4355.66

0423

MMF

1$00'11

0406 C407.04 .1

-304511411 "-I 18413 23065600 Re12.?

0444 R449 R427506 396 I0037.1101.6 "PKCONTROL

VERT. LIN.- C0071101.

C411 i-..... R 424 C,B+Z VE 1

4 T._ 680 30 _ I m...zur vrfrn 1

, 184231

I

1 ;431Pli I" Ic2W 51516 no 1

°457 L .----2#--7-71133K

40212BH7 %Er Rae66

OUTPUT #416330

4450 a ART. OUTPUT <INNt

' 3508,420V j7

I .1r.400

5. T/21S.to2E16 CRa

_,,,.....-50V 11-P 60 ' ,..

!c.:190e r.,, t 2401DEFL YOKEme ,

#460 11464 1560 MP- . 1

I

84446.80

4W

.6E00 6 GOR

6B06GTNORILOUTPUT

-_C0R440

ISO 5

-351/R4394706

18307

I

Ip

1i1Ao

4 1656

0427T.I

116

79

Ipto

2

2

.7)31-434.06 .15

- L402'WIDTH

04584006I.

C434

II

III

1.I 11i .0061 LZ8z.L.,

6AX4GT0441PER

SECTION 4 SWEEP04371.25 2

175

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONWestinghouse Chassis V-2314 and V-2324 Circuit Diagram

IRON CORE1

CHANNELS 2 THRJ 6 I

DRUM

SEGMENT

SECTION I R-F

6-(a)

C1261000

01063

..7--1C117

02476

3-9

C119

IND4.470K

R103820K

. RIGS=1.56

i24 C107L5 47 _L

L029

BOO

6U8 6827

Lim I

6U8TAIXER-OSC

ORUM SEGMENT

wr, I

L 102A

ADJ. COUP.LOOP

Ci0847

C 127

I 75

IK

FIL

800

B 145v

L 200

C

A 215 V

TUNER RETMA COOS NO. 305ALL CAPACITOR VALUES GIVEN IN MMF - 15, -25, TUNER

R32418M

4N/VW7:7C322=1, .05

300

10K

C 32302

R325 -)L5

R327

AOCCCNTROL

R 301

C3

390.

C 324I 005

6CD66 6AN8 6BK5HOR12.OUTPUT SYNC.ejFalER AUDIO OUTPUT

7 5 4 /! L501, 1.141,

A.

6.3V0A.C.

4

T0035

I2AU 7 12 AU7 6AU4GTVERT.MULTI. HORIEKRA-71. DAMPER

S 4456AU6

KEYED AOC

L502

ISO. I F

4

§106_2n IF 3RD IF

1101 TUNER L503 4

- Huh

6AL5Hos !ZAK SEE NOTE 9

NO. 55PILOT LAMP

00600 C5072800 TacoIMF MMF.

12 B 4 12AT 7 68rt 12BY 7 6AU6vERT.OUTPUT SYNC.CONT. SEE NOTE 7 EM.DET. VIDEO.AMP SMILE.

SYNC.AMP. -Z91=---12/.. 4 3 5 4 3/1I4 3 5 4 5

L50115

T.ggs

SECTION 5 POWER and HEATERS

NOTES:

117AC

LCLTAGES WILL NAM WITH CONTROL SETTING .sCARETING CONTROL,: RCTuRE TT vERT HOtD CONTROL ,1* vERT. LEN .CONTROL

2. LEAK TO REA6 55/1/E7CRATS WERE TAKEN wITH THE PICTURE CCWITROL SET FOR SIGNAL OF 609 AT THE CATHODE OF C.R.T.ALL OTHER CONTFCLS SET FOR NORMAL PICTURE.3. PARTS TOLERANCE AND RESPONSE OF TEST EQUIPMENT 400 CAUSE SONS VARIATIONS OF THE PEAK' TO' PEAK VOLTAGE REACWIGS .4. 0-C VOLTAGES MEASURED FROM CHASSIS GROLNO USING A 20,000 01.m/ LOU METER AND 150 SIGNAL INPUT.READWG5 SHOIA.0 RE AS SHOWN 0 20 PER CENT.5. ALL CAPACITANCE ALLIES IN WM Ate ALL RESISTANCE VALUES IN 01.445 ENL155 OTHERWISE 5PECIFAU6. WATTAGE RATING OF ALL i/2 WATT RESISTORS IS NOT SPECIFIED, OTHERS AS INDICATED.7. 24OP4 84 -1 CHASSIS. 2413P4 OR 240P4A IN -2 CHASSIS9 NO PILOT LAMP IN -15 CHASSIS.9 N EARLY pROCuCTION A 15 00.' v2 w RESISTOR IS 5,..E.CED A5 SHOWN 15,TH CCNTRCT t5 -22 .27C9 01 v 6.163

10 . C 326, 47MMF IS USED ONLY WITH 9879 I -F TRANSFORMERS.

SECTION 5 POWER and FIE rE S.

T 500L. V .POWER TRANS,

SW 500OFF- ON

15041.101

/000\--- C508-005500

260 vL

250 v

C502A C503440 "r_40

5U4G 6J VAC. L . v. RECT.

i20 v

Af +C436 A30 IH 4 545002 W

UK6W

54

600)6W

6AU6KEYED *GC

C435.005

18 V

R4483308

O

S'5,

6 1120V

R 452 .

95 V 1 1 594.7I

4.

R45318112W

20 V I. I,

15,750 'NE

176

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONWestinghouse Chassis V-2314 and V-2324 Circuit Diagram

6Au 615T SOUND IF IMP.

115V Ci93M6W

115 V

9V C2°2R200

.00-5

2004.746W

L 201

L 20335006

R2011.2K

C 207T .005

SECTION 2 SOUND I - F and AUDIO

6BN6R 223

FM OCT. 470 12K

C205

140 to 0.. / ---J VW. W V --j- C211

L 202 C20 .0247 661.1F 2 -1 14015

5 76 I

10,03.69.C 206

006 .7-T7,035

R202 _I_500 -.7

001E760CONTROL

L _

R2052762W

62071011

C212.01

R2043306

PAB.50 3.7

6BK5AUDIO CUTPuT

235V

720COUTPUT

TRANS.

C214Oo.003

R2065006 6014482CONTROL 206

160 30

R 210'K

- C215I .005

C:106 A

250 V

B6 T 300IT IF APP.

65 v 4 1.5,)

la R 303

3 1:

L..65V 2

4313166

4.71(

R106

S8329006

1.302SS 170

L302

47368W (SEE NOTE 0)

6086Tap ;2 NOW Ali. -10 ci,r;el

6 3 012

5

.5v

22.2

761E 830468

C30747

63064,76

T 332

6C86 r, CRYSTALC6706 iN64 14 USA

3 F A. 1110v

TC 3127

_ _t 2

1,39

C302

307161F 60

C 3081.

C:igg 1°0° IMMF

30 V P - P. 60

R 305470

T.-os

R308470

SECTION 3 VIDEO

110 V

C 311

_j_ 800- LIMP

Jill6.1.6 v. P

6060TESTPOeir

60 '1../

I2BY7VIDEO AMP

PICTURECONTROL

C 319

.02T3.9 656

220 10 2600503 L507 L290300.

CR314

2

22.1

C 3181

#3,73306

r

R 30

7.34

R31633011

1900L 19 _

R320 C320103K .25

L

939 ER1GHTNESSICOK CONTROL

FOCUS R 3 I

CONTROL 26115 70135 V

14 61

60 V. P - P 60 '14

C. R T.

= C 321

480

t0.560

84028.22

0

75

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177


WESTINGHOUSE Chassis V-2313, V2314, V-2323, V-2324, (Continued)

PICTURE

OFF -ON -VOLUME

NORIZ. NOLO

VERT. HOLD

BRIGHTNESS

NO. 55 PILOT

FINE TUNING

-t

CHANNELSELECTOR

SOCKET, PILOT LAMP

PiCTuglE

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178


EN/TH 1955 RECEIVERS

CHASSIS I9M20 - 19M20Z - I9M21 - 19M2IZ20M20 - 20M20Z - 20M2 I - 20M2IZ

CHASSIS I9R20 - 19R2I - I9R2222R20 - 22R2I

The various Zenith 1955 Chassis listed above are used in models tabulated below.All these sets are similar in design. Alignment and adjustment procedures givenapply to all chassis. Suffix I"Un indicates that a continuous tuner is used. Circuiton pages 184-185 is for the 19M series of sets. The 20M series covered by a sepa-rate circuit on pages 186-187 is similar to the basic 19M series except for horizontaloutput tube, and additional 5U4G rectifier to provide 18KV high voltage.

The circuit on pages 188-189 is exact for 19R series, 19R20 and 19R21 chassis.The 19R22 chassis is similar except that the tuner and volume control assembliesare externally mounted with plug-in cables as they are also in the 22R20 chassis.In general, the 22R series (22R20 and 22R21) is similar to the basic 19R seriesexcept for the horizontal output tube, an additional 5U4G rectifier, higher secondanode voltage, and high fidelity sound. In addition, the receivers using the 22Rchassis are equipped with phono connector, push pull audio, and different knobpositions. The waveforms and peak -to -peak voltages shown in the circuit on pages188-189 are representative for all chassis.

MODEL

M1800E or RM1800EZM180ORZM1800RZ1M2228E or RM2228RZM2229E or RM2229EZM2229RZM2230E or RM2230RZM2230RZ2M2237EZM2237RM2237RZM2249E or RM2249RZM2250E or RM2250EZM2250RZM2251EZ1M2251RZ1M2251Z1M2252E or R

TV CHASSIS MODEL

19M2019M2OZ19M2OZ19L3419M2119M21Z19M2119M21Z19M21Z19M2119M21Z19M2120M20Z20M2020M20Z19M2119M21Z19M2119M21Z19M21Z19L2819L2819L2819M21

CHASSIS MODEL CHASSIS

M2252EZ 19M21ZM2252RZ 19M21ZM2258RZ1 19L28M2260R 20M20M2260RZ 20M20ZM2261E 20M20M2261EZ 20M20ZM2267Y 20M20M2267YZ 20M20ZM2570R 20M21M2570RZ 20M21Z

R1800E & R 19R20RIME Z & RZ 19M20R1812E & R 19R20R1812EZ & RZ 19M20R2229E & R 19R21R2229EZ & RZ 19M21R2230E & R 19R21R2230E Z & RZ 19M21R2249E & R 19R21R2249EZ & RZ 19M21R2250E & R 19R21R2250EZ & RZ 19M21

R2253M 19R21R2257 E & R 19R22R2258E & R 19R21R2258EZ & RZ 19M21R2337E & R 22R20R2359E & R 22R20R2360R 22R20R2368R 22R20R2367E & Y 22R20R2387R 22R20R2391E 22R20R2671E & R 22R21R2975R 22R21R2976E 22R21R2979E 22R21R2994EU 22R21R2994HU 22R21

E - BlondH - CherryM - MapleR - MahoganyY - Ebony

SUFFIX "U" FOLLOWING ANY MODEL NUMBER INDICATES ARECEIVER EQUIPPED WITH THE ZENITH CONTINUOUS TUNER

179

MOST -OFTEN -NEEDED 195$ TELEVISION SERVICING INFORMATION

ANTENNA TERMINALS

LIO OSC. IND. TUNING

I. F OUTPUT JACK

BULL'S EYE ADJUSTMENT

R32 BUZZ CONTROL

A.C. INTERLOCK-

PHONEVISION SOCKET A.C.

FUSE

SPEAKER COMPENSATION -JUMPER WIRE

A.F C. TEST POINT( V.T. VOLT METER

CONNECTION)

A.0 INTERLOCK

REMOTE CONTROLA.G. SOCKET

R43 FRINGE LOCK

WIDTH CONTROLBRASS SLEEVE

BEAMBENDER

PI XTUBE

/1", T4 4TH I.F. TRANS. ,;6csa ASSEMBLY B

XTAL DET.VIDEO DET. TEST POINT "D'

(SCOPE CONNECTION)L20 OUADRATURE COILT3 3RD I.F TRANS.

ZENITH (Continued)

C58 HORIZONTAL DRIVE

VIDEO OUTPUTTEST POINT

"J"FRINGELOCK

ICTURE CEN-TERING AD-JUSTMENTON YOKECOVER

T2 2ND I.F. TRANS.LI I 4725 MC. TRAP-ADJ.CHANNEL SOUNDL12 39.75 MC TRAP ADJ.CHANNEL PICTURE

TI 1ST I.F. TRANS. B 41.25 MC.ASSOCIATED SOUND TRAP COIL -TOP SLUG

L6 CONV GRID IND. TUNING1 TEST POINT 'A"( I.F. SWEEP GEN. INJECTION)

R32 BUZZ CONTROL3/-L8 CONV. PLATE TUNING

'TEST POINT "H'(SCOPE CONNECTION FORRF BAND PASS OBSERVATION )

X"SCREEN FEED THROUGH

C9 CONV. GRID CAP. TUNING

gL7 MUTUAL INDUCTANCE TRIMMER

VOLUME CONTROL &ON -OFF SWITCH

FOCUS

HORIZONTAL HOLD -HEIGHT CONTROL

BRIGHTNESS

tJ

L5 R.F. PLATE IND. TUNING

CB R.F. PLATE CAP. TUNINGLI7 SOUND TAKE -OFF COIL

- C5 R.F. GRID TUNINGLI9 INTERCARRIER COIL

CHANNEL SELECTOR

FINE TUNINGA.G.C. DELAY CONTROL

CONTRAST CONTROLVERTICAL LINEARITY

- VERTICAL HOLD

*TEST POINTS USED INPRODUCTION

Fig. 4 Tube And Trimmer Layout 19M20, 19M20Z, 19M20U, 19M2OUZ, 19M21,19M21Z, 19M21U, 19M21UZ & 19M22UZ.

180


Zenith 1955 Chassis (Continued)

FRINGE LOCK ADJUSTMENT1. Turn the fringe lock control fully clockwise andthen back it off approximately 1/4 turn. Adjust thevertical and horizontal hold controls and checkoperation of the receiver to see that it syncs normal-ly when the turret is switched from channel tochannel.

2. If the picture jitters or shows evidence of delay,tearing, split phase, etc., back down the fringe lockcontrol further, a few degrees at a time, each timere -adjusting the hold controls and switching fromchannel to channel until normal sync action is ob-tained. It will be found that under normal signal con-ditions, the correct adjustment will be near thecounter -clockwise position of the control.

3. In fringe and noisy areas,. the best adjustmentwill be found at or near the maximum clockwiseposition ci the control, however, do not automaticallyturn the fringe lock fully clockwise in fringe areasas has been done on previous models. Always followthe procedure outlined.

BULLS EYE TUNER ADJUSTMENTSTo adjust the receiver for bulls -eye tuning, set thefine tuning control to its approximate center positionas shown in Fig. 1 . Without further adjustment ofthe fine tuning control insert a 68-21 alignmentwrench into the tuner (See Fig. 11) and adjust eachoperating channel to resonance. It will be noted thattuning to one side of resonance results in a faded,washed-out picture with the spacing between thewedge lines fogged and tuning in the opposite directioncauses the spaces between the lines to clear up.However, going beyond this point causes the pictureto take on a "wormy" appearance from sound gettinginto the picture. Correct adjustment is obtained bytuning to the "wormy" picture and then backingthe control off slightly until the picture clears up.

68-21 AlittVent Wren

Fig. 11 Bulls -eye Tuning Adjustment

AGC ADJUSTMENTSIMPORTANT: THE AGC CONTROL CANNOT BEUSED IN ANY WAY TO IMPROVE THE RECEIVERSENSITIVITY. The sole function of this control isto set the level applied to the video amplifier (12BY7)tube so that the output of this tube is approximately100 volts peak (100% modulated video signal) forapplication to the picture tube cathode.The adjustment can also be made by connecting a cali-brated oscilloscope through a 10K isolation resistor,to test point "D" , and, while receiving the strongestTV signal adjust the AGC delay control for 2.75 voltspeak output.

Satisfactory adjustment can also be made by observingthe picture and slowly turning the AGC delay controlfrom its maximum clockwise position, counterclock-wise until a point is reached where the picture dis-torts and buzz is heard in the sound. The controlshould then be turned slowly clockwise and set at apoint comfortably below this level of intercarrierbuzz, picture distortion and improper sync.

REMOVING CHANNEL STRIPS1. Rotate the turret drum until the strip to be re-moved is readily accessible.

2. Insert a small screwdriver in the slot (S e eFig. 13). Push in the direction of arrow until thechannel strip clears the drum slot then lift straightout in direction of screwdriver shaft. Some stripshave a round hole instead of a slot and a pointedtool is used in place of the screwdriver.

CAUTION: TO AVOID DAMAGE TO CHANNELSTRIPS, DO NOT USE PRYING ACTION IN RE-MOVING STRIPS.

Fig. 13 Removing Channel Strips.

181


ZENITH 1955 Chassis (Continued)

ALIGNMENT

TO RECEIVER ANTENNA TERMINALS

MATCHING TRANSFORMER50 OHMS UNBALANCED TO 300 OHMS BALANCED

HOOKED ENDFOR CONNECTINGTO VARIOUS GRIDS

470 MMFD.CERAMICCAPACITOR

GROUND DIRECTLYTO CHASSIS. DO NOTUSE LEADS.

56f).1/2 W 57.CARBONRESISTOR

SWEEP GENERATOROUTPUT CABLE

Fig. 14 IF-RF Alignment Fixtures

A suitable VHF and UHF sweep generator in con-junction with an accurate marker must be used foralignment work. It is very important to have thesweep generator output cable properly terminatedand to check whether or not its attenuator is reactive.If the attenuator is reactive or if the output cable isimproperly terminated, correct alignment cannot bemade since the degree of attenuation then may changethe shape as well as the amplitude of the responsecurve. The position of the attenuator should onlyvary the amplitude and not the shape of the responsecurve.

SOUND ALIGNMENTProper alignment of the 4.5 Mc intercarrier soundchannel can only be obtained if the signal to the re-ceiver antenna terminals is reduced to a level belowthe limiting point of the 6BN6 Gated Beam Detector.This level can be easily identified by the "hiss" whichthen accompanies the sound.

Various methods may be used to reduce the signallevel, however, it is recommended that a step atten-uator similar to the S-17203 unit be used for mostsatisfactory results.

1. Connect the step attenuator between the antennaand the receiver antenna terminals.

2. Tune in a tone modulated TV signal and adjust thestep attenuator until the signal is reduced to a levelwhere "hiss" is heard with the sound.

3. Adjust the sound take -off coil L17 (top and bottomslugs), intercarrier coil L19, quadrature coil L20and buzz control R32 for the cleanest sound andminimum buzz. It must be remembered that any ofthese adjustments may cause the "hiss" to disappearand further reduction of the signal will be necessaryso that the "hiss" does not disappear during align-ment.

If intercarrier buzz is in evidence, after all normalsound adjustments have been made, the cause may beattributed to one or more of the following:

1. Improper adjustment of the AGC delay control.

2. Defective 6AU6 sound limiter.

3. Extremely high signal levels which require atten-uation in the antenna circuit.

4. Transmitter over modulation.

VIDEO IF ALIGNMENT1. Slowly turn the channel selector until the turret ismade to rest between two channels. Connect the neg-ative lead of a 2 volt battery supply to terminal "E"(Fig. 27) and the positive lead to chassis. The biassupply should be made variable so that it caR bevaried from negative 3 volts to positive 3 volts. Keepthe supply leads short.2. Connect the calibrated oscilloscope through a10,000 ohm isolation resistor between terminal "D"and chassis. The sweep generator input to the re-ceiver should be adjusted for 3 volts peak to peakdetector output. Do not exceed this output levelduring any of the adjustments.

3. Feed the output from the sweep generator throughthe special termination unit shown in Fig. 14 to point"C" (Pin 1 of 6CB6, 3rd IF). Adjust the generatoruntil a pattern similar to Fig. 16 is obtained.

75MC 45 75MC

Fig. 16 4th IF Response.

4. Set the Marker Generator to 45.75 Mc and alter-nately adjust the top and bottom slugs of the 4th IFtransformer for maximum gain and symmetry withthe 45.75 Mc markers positioned as shown in Fig. 16The 39.75 Mc marker can be within 1.0.5 Mc of thespecified frequency. If the correct response curvecannot be obtained in this step, check the position ofthe two slugs to see that they are entering theirrespective coils from the opposite ends of the coilform. The position of the slugs near the center of thecoils may change the coefficient of coupling, makingcorrect alignment difficult if not impossible.

182


Zenith Chassis 19M20, 19M20Z, 19M21, 19M21Z, 20M20, 20M20Z, 20M21, 20M21Z,19R20, 19R21, 19R22, 22R20, 22R21.

5. Connect the sweep generator cable to terminal"A" (Mixer Grid). In this step it may be necessary totemporarily reduce the bias to zero or even to go toa slightly positive voltage in order to see the highlyattenuated trap slots with the oscilloscope verticalgain near maximum.

6. Adjust the 47.25 Mc, 41.25 Mc (Top slug of 1stIF transformer) and 39.75 Mc traps for minimummarker amplitude, See Fig. 17 . It can be seen thatmaximum oscilloscope gain has been used and as aresult the top of the response curve has been "runoff" the oscilloscope screen in order to see a "blow-up" of the trap slots.

Fig. 17 Exploded View of Traps.

7. Readjust the bias to -2 volts and set the oscillo-scope vertical gain to the calibrated position. Adjustthe sweep generator for a 3 volt peak to peak outputfrom the video detector.

8. With the test equipment set up as in Step 7, alter-nately adjust the 2nd IF, 3rd IF, 1st IF and the conver-ter plate coil until an overall response curve similarto Fig.18 is obtained. Do not adjust the 4th IF in thisstep. It will be found that the 2nd IF affects the lowside (42.75 Mc) and the 3rd IF the high side of theresponse curve.

/11/4 45 75MC

42.75MC 45MC

Fig. 18 Overall IF Response.

TURRET TUNER ALIGNMENTThe RF chassis adjustments have been made at thefactory and normally do not require readjustment inthe field unless tampered with. If adjustment becomesnecessary check the overall IF response and proceedas follows:

1. Temporarily ground the turret AGC by connectinga jumper between the AGC bus (yellow lead) andchassis. (If sufficient output from the signal genera-tor is available moderately better results may be ob-tained with 2 volts of bias.)

2. Connect the calibrated oscilloscope to the feedthrough terminal "H" (Fig. 4 ) through a 10K isolationresistor. This terminal is the screen of the 6U8mixer.

3. Use a 50 to 300 ohm matching transformer(Fig. 14) and feed the output from the sweep gen-erator to the antenna terminals of the receiver.

4. Turn the channel selector to Channel 4 and adjustthe sweep generator until a response curve somewhatsimilar to Fig. 19 is obtained.

Fig. 19 Channel 4 RF Response.

5. Study Fig. 4 and adjust the converter grid capaci-tor (C9), the RF plate capacitor (C8) and the RF gridcapacitor (C5) until a response curve similar toFig. 19 is obtained.

6. Turn the channel selector to Channel 11 and adjustthe sweep generator until a response somewhatsimilar to Fig.20 is obtained. Adjust L5 and L6 toobtain symmetry. If the band pass is too great or toonarrow also adjust L7.

Fig. 20 Channel 11 RF Response.

7. Repeat steps 5 and 6 until the best overall sym-metry is obtained. REMOVE AGC JUMPER.

MASTER OSCILLATOR ALIGNMENTThe master oscillator adjustment is to be made onlyif resonance cannot be obtained with the strip oscilla-tor adjustment wrench with the fine tuning control inits center position, and after it has been determinedthat the channel strip itself is not at fault.

If channels 2 through 6 can be made to resonate withthe bull's-eye adjustment at the rear of the turret andthe high channels do not resonate, a slight readjust-ment of the oscillator inductance L10 (See Fig. 4 )

may be necessary to affect resonance on the highchannels.

183


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NOTES

ALL VOLTAGES MEASURED FROM CHASSIS TO POINTS INDICATED.ALL VOLTAGES ARE DC UNLESS OTHERWISE SPECIFIEDALL DC VOLTAGES TO BE MEASURED WITH VACUUM TUBE VOLT-

METER HAVING II MEGOHM INPUT RESISTANCEALL VOLTAGE MEASUREMENTS TO BE MADE WITH NO SIGNAL

PRESENT NORMAL SETTING OF CONTROLS AND CHANNELSELECTOR SET TO 2 UNLESS OTHERWISE SPECIFIED

ALL CONDENSER VALUES IN MICROFARADS UNLESS OTHERWISESPECIFIED

ALL RESISTORS720% TOLERANCE UNLESS OTHERWISE SPECIFIEDALL CONDENSER CAPACITY TOLERANCE 20%UNLESS OTHER-

WISE SPECIFIEDALL RESISTORS I/2 WATT UNLESS OTHERWISE SPECIFIED.RESISTANCE MEASUREMENTS SHOWN WITH COILS DISCONNECTED

FROM CIRCUITCOIL RESISTANCES NOT GIVEN ARE UNDER ONE OHMCATHODE RAY TUBE 2ND ANODE VOLTAGE TO BE MEASURED WITH

ELECTROSTATIC OR 208 WIN OHM PER VOLT HIGH VOLTAGEMETER

ARROWS ON POTENTIOMETERS INDICATE CLOCKWISE ROTATION

® CIRCLED ALPHABETS INDICATE ALIGN PENT ANDPOINTSA LIGFIM%N7.

TEST POINTS

TO SO oarON SOUNDTAKE OFFCOIL.

Schematic Diagram Chassis 19M20, 19M21, 19M20U & 19M21U.

V7A6

SPI6UD.

LIM.

7

111 VACINTERLOCK

35 AMPS

NPA,CI2"E

01

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In the 19M series, the centering assembly is builtinto the yoke housing. This assembly is made up oftwo magnetic rings which can be rotated by means oftabs. Centering is accomplished by gradually ro-tating the tabs with respect to each other then rotatingboth tabs simultaneously until the picture is centered.

FOCUS CONTROL: In the I9M Series, a 7.5 Megohmpotentiometer is provided for focusing the picturetube.

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UHF-VHF CHANGEOVER SWITCH

The low loss 85-546 UHF -VHF changeover switch ispart of the S-21001 UHF -VHF tuner package. Theswitch performs 3 functions.

1. Is used to switch the antenna between tuners.2. Switches the oscillator Bi- between tuners.3. Actuates the UHF pilot light.

The switch is actuated by a lever whichis mounted on the turret tuner shaft. When the VHFtuner is in the UHF position, the lever, if properlyaligned, will actuate the changeover switch.

184


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ZENITH Chassis 19M20, 19M2OU, 19M21, and 19M21U.Chassis 19M20Z, 19M2OUZ, 19M21Z, and 19M21UZ,are similar but have a socket for UHF tuner connection.

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mEC 2"L21HOME IUD mks,

HOLD

860 I C27

2741 .001288

c24

VI4A6SN7GT

NORM On.

-58V

801'

44350

VI45 VI51/2 6SN7GT IS 6 BO6GTNORIE.DISCH. HORI Z. OU

476

R2619CST

..--1220

3 1AMF

_ cs. s'°%- 680

inw Cip.HORIZ10% DRIVE

TRHADEER

R62

R52

100

:SySK

REMOVING TURRET TUNERFROM THE CHASSIS

1. Pull out the VHF power connector, UHF IF con-nector, VHF oscillator B+ connector, VHF IF con-nector and disconnect the antenna transmission line.

2. To insure proper indexing, note the channel towhich the receiver is tuned so that the tuner drumcan be rotated back to this channel before the unitis reassembled.

3. Loosen (do not remove) the hex head set screw inthe VHF tuner drive pulley and slide pulley off the finetuning shaft. Remove screws and hex nuts .

MA

FUSE

4. Gently pull the tuner out of its case

11

139

Cl5i9

047

7.3288

no c 31c10 NIFD

I B3GTVI6 475 v

H.V. RECT.

TO N v 1469

8 V IT5 6AX4GT

DAMPER A+5006

TTi

HORIZONTALDEFLECTION

COILS(BRASS SLEEVE

2/10TH CONTROL)

If, after the tuner is reinstalled, the fine tuningknob does not have normal mechanical travel (fromstop to stop of the lower pulley) and can be turned tohit only one stop, the dial cord can be made to Sliptowards the other stop by applying sufficient pressureto the fine tuning knob.

METAL WRAPPED RESISTORS

In servicing the TV receiver, the serviceman will findseveral circuits in which metal wrapped resistors areused. The metal wrapping dissipates much of theresistor heat and doubles the wattage rating. Inreplacing a resistor care should be used to mount itas the original. If the metal mounting clamp is dis-carded, the resistor wattage must be doubled.

R6533K

185

MOST -OFTEN -NEEDED 19SS TELEVISION SERVICING INFORMATION

C 11`100

4111OSC

f ell

VII6CD"

HOIN2 OUT

Vva'r-

VIAAIN TOT

MSC

RT

vlx

9AVDT

II CONTROL

G A'SIND

11416TWIT

v36C961IT T

GILSSOt9.01.91

MIZTDAMPIER

vt.6<S6

SYNC 411.

Prj. YL'YitiV ANTENNA

1---'-172;01?YrR F GRID

F T DENOTES FELDTHROWN TYPE OFCERAMIC CONDENSER

A0010 FORCOININATION3

ONLY

1/2

C

RS229

VIBLS

6BK7R.F.

COAXIAL CABLO

OSCILLATOR FEED FIM

;zarz,feyervr. 'wets

ITCH ON VOLUMECONTROL

°TN Vc .0R4C121,9!in

V2A1/2 6U8

cto MIXER2

VIES5U4GL.V.

RED RECT.

Schematic Diagram Chassis 20M20 4 20M20U.

CENTERING ADJUSTMENT

In the 20M series, PM focusing and centering isutilized. The top screwdriver adjustment on thecentering assembly is used to move the picture upor down and the bottom adjustment for side to sidemovement. The center adjustment is for focusing.

In some 20M21 receivers, a single centering leveris used for both vertical and horizontal centering.The up -down movement of this lever moves thepicture horizontally while a left -right movementmoves the picture vertically. A screwdriver adjust-ment is provided for focusing.

AFC ADJUSTMENT

The AFC adjustment can effectively be made by set-ting the horizontal hold control L21 to a positionwhere it is virtually impossible to "throw" the re-ceiver out of horizontal sync when switching fromchannel to channel.

OSCILLATOR

C15

ltrr̀1/213

1/2 6UOS

1:=';;17"" 'Alf.L.T.XT"-"r""

I fr

2 2 5E6

V36CB61ST

V86AU6 6BN6

SOUND LIM. SOUND DISC.

YIN It

VI95U46L.V.

RECT.

///scoto 230V

CrTIS TI2 CSC

00 V LT' 184n.

1 / 2 612117 G TA.f.C.

Adjustments on Neck of PictureTube 20M21 Chassis

CSI00T0%

INT

rz

"'own,

CS1001

R39

10%

CIO

01

CN

186

IMOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONZENITH Diagram for Chassis 20M20 and 20M20U. Chassis 20M21, 20M21U, and20M21Z are similar in most respects; some of the differences are the use of 24CP4or 27EP4 picture tube, and 6AU5GT or 6AV5GT vertical output tube.

V46C111 6END I.F.

VS6C86

3RD I.F.

r

L

R24*21410%

V612 BY 7

VIDEO AMP

IS

64

5K10%2w

xirr

R 4633%6

10

10%

1111CrAO

62766 ICc

CON-TRASTCON6SOL

142

SRe

+ 250V

CF4

REJlnS

2046

V202IEP4A OR

21EP4111PI X

375

Note: 20M21Z uses aturret type tuner.

0. TO MV

R 106

V9'SDKS

SOUND OUT.

V1OA1/2 I 2A X7

A.G.C. R5

stsisSYNC. CLIP. R45 al

IOB1/2

VI2AX7

C2 VERT. OSC.

VI 2 R30 410,11

6AH4GTVERT. OUT.

T6

I IV

4110610%

690900

c% 75 YEG

272

7060%

Ted

irrga, 15'0

FRINGEOCR

R2

10%0%

R6

0%

646

c5

R76$506

090%3 qo

7314 q-vERT

HO' C69247K

250v

C7X001

lue

2280%

MEG

RSO

o,L

loo

R1770

qp

10%

rnc. r500 10R5

LIME66vv1,

C656 r; R7600 SAD ss

ax

00 v

T.VERY

089 LEL71010COILS

VI4A9I/2 6SN7G

H

C54 'a IW111411111rwt 15oorrr

R5

L2, ii SC461:/r re

IORIZ la%NOLO10LO

.0 C27

001

2206

K

VI4B

t425V

/2 6SN7GTHORIZ.DISCH.

10% 961

60014

VIS6C060

666700

71

VI1936GTH.VRECT.

RA,VOX3 3 10%

C650Morro

71

C047 109.

V176AX4GTDAMPER

ra 15

viii74±"MORIZ LIN.

REMOVING THE 521000 CON-TINUOUS TUNER FROM THE CHASSISAlthough it may be more convenient to first take outthe VHF tuner before removing the UHF tuner it is nota necessity. The UHF tuner can be removed asfollows:

1. Loosen the screws and hex nuts which hold theVHF tuner in place. Loosen the VHFtuner drive pulley and slide the pulley off the driveshaft. This step is necessary so that the VHF tunercase can be moved slightly to obtain clearance forremoval of the UHF tuner.

2. Remove the UHF heater and B+ connections

3. Loosen the set screw and remove the UHF tunerdrive pulley.

III C6015

10%

314

NORIOE FLECTiosCOILS

Ill

ash

3K

NOTESALL VOLTAGES MEASURED FROM CHASSIS TO POINTS INDICATED.ALL VOLTAGES ARE D.C.UNLESS OTHERWISE SPECIFIECALL DC VOLTAGES TO BE MEASURED WITH VACUUM TUBE VOLT-

METER HAVING II MEGOHM INPUT RESISTANCE.ALL VOLTAGE MEASUREMENTS TO BE MADE WITH NO SIGNAL

PRESENT NORMAL SETTING OF CONTROLS B CHANNEL SELEC-TOR SET TC 2 UNLESS OTHERWISE SPECIFIED

ALL CONJENSER VALUES IN MICROFARADS UNLESS OTHERWISESPECIFIED

ALL RES1.TORS C 20% TOLERANCE UNLESS OTHERWISE SPECIFIED.ALL CONDENSER CAPACITY TOLERANCE I.20% UNLESS OTHERWISE

SPECIFIED.RESISTANCE MEASUREMENTS SHOWN WITH COILS DISCONNECTEL

FROM CIRCUITCOIL RESISTANCES NOT GIVEN ARE UNDER ONE OHM.CATHODE RAY TUBE 2ND ANODE VOLTAGE TO BE MEASURED WITH

ELECTROSTATIC OR 20K MIN. OHM PER VOLT HIGH VOLTAGEMETER.

ARROWS ON POTENTIOMETERS INDICATE CLOCKWISE ROTATIONALIGNMENTPOINTS CIRCLED ALPHABETS INDICATE ALIGNMENT AND

TEST POINTS.

4. Remove the UHF tuner locking screw and lift upthe tuner. It may be necessary to bear slightlyagainst the VHF tuner case to obtain sufficient clear-ance for removing the UHF tuner.

When the tuner is reinstalled, reverse this procedure.Do not tighten the UHF tuner locking screw until theVHF drive pulley is installed and can be movedfreely. Also do not tighten the UHF tuner drivepulley until the tuner and the indicator dial are insynchronism on channels 14, 54 and 83.

187


ANTENNA

VOLTAGES MEASURED WITH V T vMAPPRO1 10K/L I/2W ISOLATION RESISTOR(LEAD ON MEASURING END OF RESISTORMUST RE SHORT 1/4 INCH OR LESS I

V2GUS

VI61117A

01568066T

VS28,8'7

V14GSN7ST

V9HAGS

IN60/27GT

VII68E6

ROsl

V3SCRS

S31AL7M

VIISBNS

VI9

PIN

VI21254

VI7680407

VIO12AX7

2

1 ,1

i

1

Tri-, GRID COILS N

JAS USED ONCHANNELS 2.40

O 0

O 0O 0

O 0

O 0

O 0

O 0

0

0

NSFMYF

_11 4

I

L ). JANTENNA,/

gRFRIP-R-F GRID COILS AS v leussg ON "A""EV/2 68K7A

R. E

PiaC2

VIACGI 21).

/2 GMV

' 6BK7A5%

L

R. F.As -0.v10% . III J/

'0%, e.v.k_si eiza 46..M. 'jiff GMV FTET F THMV ASV

221

LS

233

-25 YO -7 V DEPENDING ON CHANNELNO, VINE YUNER, A HULL'S EYE serrING

COAXIAL CAILE

CrSCR-CAM,Pr vren-61rorp--/,`TY:0--R F PLATE IRS MI - CONVERTER

404 TAB ON SHIELD

-II Wk."L7 !29%

1/2 6U8 VU

/201/

L4

R

--1

H a(I 2 3I NSF

DI BOOMMF FT GMV

V.

100110%

12

Ls

RS70

C9

6-30NSF

coM1XER_ 1/2 6U82111MF 6 OC.10% 240 V

1042

R6100110%

121ION.

BOOMMFFTGrV

1,,

no LSIMO

CIS55MMF525

y.10 VII

23V

1(24111Es:3

4

CI4

I345 NNW.,

C11

R682 211

112

NE TUNING

LIO

R61101

SCI7 j]MMFIi

L

R9

A G C

220 C800 IMFFT GNI/

250 V

CISMMF

141Z. Lill

2411KIF5%

F T DENOTES FEED THROUGHTYPE OF CONDENSER.

NOTES

ALL VOLTAGES MEASURED FROM CHASSIS TO POINTS INDICATED.ALL VOLTAGES ARE DC UNLESS OTHERWISE SPECIFIEDALL DC VOLTAGES TO BE MEASURED WITH VACUUM TUNE VOLT-

METER HAVING 11 18880181 INPUT RESISTANCE.ALL VOLTAGE MEASUREMENTS TOSE MADE WITH NO SIGNAL

PRESENT NORMAL SETTING OF CONTROLS AND CHANNELSELECTOR SET TO 2 UNLESS OTHERWISE SPECIFIED

ALL CONDENSER VALUES IN MICROFARADS UNLESS OTHERWISESPECIFIED.

ALL RESISTORS320% TOLERANCE UNLESS OTHERWISE SPECIFIEDALL CONDENSER CAPACITY TOLERANCE t 20%0NLESS OTHER-

WISE SPECIFIEDALL RESISTORS I/O WATT UNLESS OTHERWISE SPECIFIED.RESISTANCE MEASUREMENTS SHOWN WITH COILS DISCONNECTED

FROM CIRCUIT.CON RESISTANCES NOT GIVEN ARE UNDER ONE 021MCATHODE RAY TUNE 2ND ANODE VOLTAGE TO RE MEASURED WITH

ELECTROSTATIC OR 201 MIN OHM PER VOLT HIGH VOLTAGEMETER

ARROWS ON POTENTIOMETERS INMATE CLOCKWISE ROTATION

"SlEi

peAlaLtitifsn crECsliED,ctliNSIXIDETS INDICATE ALIGNMENT AND

TO SOMMEON SOUNDTAKE OFFCOL

SWITCH ONVOLUME CONTROL

R37

Schematic Diagram 19R20 & 19R21 Chassis.The 19R22 chassis is similar except that the tuner andvolume control assemblies are externally mounted withplug-in cables as the 22R20 chassis. Waveforms andpeak to peak voltages are representative for allchassis.

6AU6 TCIGAs.

M"SNO.SSP IGNY

Fl

I7 VACINTERLOCK

RIO1001

7

35 AMPS

FYI

713

1.19

X001

R22

1

vs6BN6

SNO. DISC. R34

61110

ors

G PEP

01

-0 5114 GA

OR5049

L. V. RECT.

1332212W

VII

:AST.OI

R37to

MEGVOL

CON

R3668010%

LSO

rev 1W

CENTERING ADJUSTMENTIn the 19R series, the centering assembly is builtinto the yoke housing. This assembly is made up oftwo magnetic rings which can be rotated by means oftabs. Centering is accomplished by gradually ro-tating the tabs with respect to each other then rotatingboth tabs simultaneously until the picture is centered.

In the 22R series, PM focusing and centering isutilized. The top screwdriver adjustment on thecentering assembly is used to move the picture upor down and the bottom adjustment for side to sidemovement. The center adjustment is for focusing.

435 AMPS.

TV

GOA

CM.IMIU 40

MFD400104P.

C49100S10%ri

18:4110;

r:111111-0,.,

In some 22R20 and 22R21 receivers, a single centeringlever is used for both vertical and horizontal center-ing. The up -down movement of this lever moves thepicture horizontally while a left -right movementmoves the picture vertically. A screwdriver adjust-ment is provided for focusing.

AFC ADJUSTMENTThe AFC is adjusted by setting the horizontal holdcontrol L21 to a position where it is virtually imposs-ible to "throw" the receiver out of horizontal syncwhen switching from channel to channel.

188

1.12


60w

C2I29 LOAF'Si RI5

LMJC3219

10 MFO400 V

VS6CB61ST I.F.

ZENITH Diagram for Chassis 19R20, 19R21, and 19R22. Chassis 22R20 and 22R21are similar except for the horizontal output tube, an additional 5U4G, higher secondanode voltage, and high fidelity sound.

BO4- M%

11`,856.

VISA/2 6AC)7GT

A.F. C.092v

J

93942010%

V46CB6END I.F.

R20120010%

11597910%

I Wmy

VIOA1/2 I2AX7

I A.G.C.

C54

690 9191F10%

R42156

A C091801

1.21 I INCROR12

HOLD

R60

10k2W

VS6CB6

3RD I.F.

9232705% C2

00

96

T

Knob positions also differ.L17

C!0

MMF 95C29 MM

giMMFX 01

R705600

C28 Ty,

VII6 BE6

SYNC.CLIP

Lsv336

O%

V14AV2 6SN7GTNORILOSC.

L141LID

//HI2700 J .25

0%56 0%

90

C31A-4WD350 V

C94TO1341 R6r6

C 339)".' 4-W. 9 31.9F

V19

VSI2BY7

17 LP421 YP4

495:

VIDEO AMP KtLiEl 136490 PI%

TO H V

"WV

SYNC. PULSE WITH VERT

Wl'UT SHORTED V10S

1/2 12AX7VERT. OSC.

0093

R40 R224706

-5 ro KV OCPCNOFNO UPON FRO/OfLOCK .1( (7,4 I

R 6VERT IC NJ

SIZE I

4704 175 t0%

VI4SV2 6SN7Gtit:Ma. DISC

CORRECTOR MAGNET ADJUSTMENT

Two corrector magnets are used (not required in the19R series) to obtain straight, sharply focused sweeplines across the face of the picture tube. In the22R21 chassis, the corrector magnets are mountedtop and bottom. The magnets are mounted on thedeflection coil mounting brackets and can be movedin and out or up and down by bending the flexiblearms which support them. Adjustment has been madeat the factory and should not require re -adjustmentunless accidentally bent out of position. If thisoccurs, proceed as follows:

1. With the vertical and horizontal size controls,reduce the size of the picture to a point where the

HORIZDRIVETRIMMER

inSLO-6L0 FUSE

ACS.44 047

10%R47

CEI975966

0%R63i2610%

R2920069610111NE5

CONTROL

VIP12134

VERT. OUT.NC06.37

0%

1176 1VERT250 1LIN

0316100 MED50 V

C 3IC

V1610 4WD475 V

IB3GTN.V. RECT.

TO 11 V ITKV

VI?5 6AX4GT

DAMPER4- 500 V

5 5 Lin

T7

VERTOEFLCOLS

HORIZONTALDEFLECTION

COILS(BRASS SLEEVE

WIDTH CONTROL/

four corners and sides of the picture are visible.(In some receivers it may not be possible to reducethe picture size sufficiently to see all the sides andin this case it may be necessary to shift the picturewith the centering control to view one side at a time.)

2. Bend the corrector magnet arms until the cornersbecome right angles and the top of the raster isparallel with the bottom and the left side is parallelwith the right side. After adjustment, the pictureshould be restored to normal size.

NOTE: Mis-adjustment of the corrector magnetsmay cause pincushioning, barreling, keystoning, poorlinearity, etc.

189


ZENITH RAD 10 CORPORATIONThis signal path chart will help you diagnose faults that may develop in the 1955Zenith television models.

AUDIODET.

,''73N6C136; 1ST. I.E.

: V4 *.

;6CB6:2ND...1 V5 %,3RD I.F.t6CB6;

1 DET. OUTPUCon nD 0****

It

4

R F . t*t.

" "MODELS 6AF4ONLY $ I t

...I.* 44.

0 SC.VIDEAMP

V202IEP4A OR2IEP4B

PIX

..""?VII -s

(FRINGE LOCK6 S6

#GATE)

:SYN

*4

AFFECTS PICTUREAND SOUND

1M a MM.

f A.G.C.ls%.

12VAI

SOUND OUT-PuT

VERT. -I'S

HORIZ.OUTPUT

V ERT. OUT.

t TOVERT.YOKE

DISCHARGE

18

146

LOW VOLTAGE RECT

V19

5U4G

LOW VOLTAGE RECT.

VERTICAL CIRCUIT ««« SOUND CIRCUIT ------HORIZONTAL CIRCUIT COMPOSITE VIDEO "A"A*WATTS 235 VOLTS- 117 A.G. 60 CYCLES

Signal Path Chart 20M20, 20M20Z, 20M2OUZ & 20M20U.

190


Index Under each manufacturer's name are listed that make chassisand models in numerical order, at left. The corresponding pagenumber at right of each listing refers to the first page of each sec-tion dealing with such material.

Admiral Corp. Armiral, cont. CBS, continued Emerson, cont. Majestic, cont.19L2,19L2Z 11 T2242BZ 10 921-13 31 798B 47 88 7319M2 11 TA2242 11 921-14 31 120179B 47 123 7319N2Z 11 CA2246 11 120203B 47 124 7319R2 11 C2256 10 Crosley Corp. 1202048 47 124-2 73

G-17T0B 351952 11 K2256 10 120205B 4719T1, -C 11 K2257 10 G-17TOBK 35 Montgomery Ward19W1, -A 11 CA2526 11 G-17TOBU 35 GEneral-Electric WG-3071E,-F 7719W1B, -C 11 G-17TOMH 35 F 57 WG-3073E,-F 7719Y1A 11 Arvin G-17TOMU 35 G, J, K 63 WG-3075D,-E 7720A2, 20A2Z 5 21-550 25 G-17TOWEH 35 17C127 57 WG-3077D,-E 7720D2 5 21-551 25 G-17TOWH 35 17T14 63 WG-3079D,-E 7720L2 11 21-552 25 G-17TOWU 35 17T15 6320X5 10 21-553 25 H-17TOBH 35 17T16 63 Motorola, Inc.20X5A, -B 10 21-554 23 H-17TOBU 35 17T20 63 17T20 8520X5C 10 21-555 23 H-17TOMH 35 17T115 57 Yl7T20 8520XP5A 10 21-557 23 H-17TOMU 35 17T117 57 21C3 79TA1811 11 D-379 25 H-17TOWH 35 21C103 63 21K19 85TA1812 11 D-382 25 H-17TOWU 35 21C104 63 21K20 79TA1822 11 E-383 23 G-21TOBH 35 21C114 57 21K21 79T1331 10 G-21TOMH 35 21C115 57 21K22 79T1832 10 Canehart- G-21TOWH 35 21C116 57 21K23 79T1842 10 Farnsworth H-21COBH 35 21C117 57 21K24 79TA2211 11 1T174+ 27 H-21COBU 35 21C119 57 21T15 85TA2212 11 2T214+ 27 H-21COMH 35 21C120 57 21T16 85T2212B 10 4C174+ 27 H-21COMU 35 21C121 57 21T17 85CA 22152 11 5C214+ 27 H-21COSBH 35 21C350 63 21T18 79LA2215Z 11 9F214+ 27 H-21COSH 35 21C351 63 21T19 79TA2215 11 15W214+ 27 H-21COWH 35 21T10 57 Y21C3 79C2216AZ 5 16T244+ 27 H-21COWU 35 21T11 57 Y21K19 85GA2215Z 11 18W214 27 H-21HCBH 35 21T12 57 Y21K20 79HA2216Z 11 CX-37 27 H-21HCBU 35 21T14 57 Y21K21 79K2216A 5 CX-37-1 27 H-21HCMU 35 21T15 57 Y21K22 79KA2216 11 CT -89 27 H-21HCWH 35 21T17 63 Y21K23 79LA2216Z 11 CT -90 27 H-21HPBHa , d 35 21T18 63 Y21K24 79T2216A 5 CT -95 27 H-21HPWHa,d 35 21T19 57 Y21T15 85TA2216,-A 11 CT -108 27 426 35 21T22 63 Y21T16 85CA2217Z 11 CT -110 27 431 35 21T23 63 Y21T17 85HA2217Z 11 CT -112 27 431-2 35 21T24 63 Y21T18 79K2217A 5 CT -115 27 432 35 21T25 63 Y21T19 79KA2217 11 CT -116 27 443 35 21T30 63 24K4 79LA2217Z 11 CT -130 27 443-3 35 21T31 63 24K5 79T2217A 5 CT -131 27 445 35 Y24K4 79TA2217,-A 11 CT -133 27 Hallicrafters Y24K5 79TA2218 11 CT -134 27 Du Mont Labs. 17T310 69 TS -418 85TA2222 11 RA -312 43 21T320 69 VTS-413 85F2226 5 CBS -Columbia RA -313 43 21K330 69 TS -518 85FA2226 11 22C09, -B 31 A1600D 69 VTS-518 85KA2226 11 22T19, -B 31 Emerson Radio B1600D 69 WTS-518 85TA2226 11 U22C05 31 748B, -C 47 RTS-525 79KA2227 11 U22C07 31 777B 47 Majestic TS -525 79C2236A 5 U22T09 31 787A, -B 47 78, 78A 73 WTS-525 79CA2236,-A 11 U22T19 31 796C 47 79 73 TS -528 79GA2237 11 921-11 31 797B, -C 47 81 to 86 73 TS -603 79

191

MOST -OFTEN -NEEDED 1955 TELEVISION SERVICING INFORMATIONOlympic Radio RCA, continued Sears, cont. Trav-ler Radio WeR, S, U 89 213505(U) 121 4150E 133 47A3 167 H-881KU24 17117CR20 89 21S506(U) 121 4153E 133 48A3 167 V-2313 17117TR10 89 213517 (U) 121 4155E 133 48A4 167 V-2313-15 17117TR19 89 215518(U) 121 5113 133 48C4 167 V-2313-25 17121CS12 89 213519(U) 121 528.271 133 49A4 167 V-2313-35 17121CS18 89 215521(U) 121 528.292 133 V-2314 17121CU15 8921CU16 8921KS22 89

21S522(U) 121218525(U) 121213525(U) 121

528.300 133528.303 133 Westinghouse

V-2314-15 171V-2314-25 171V-2323 171H-838K21B 171

21TS11 89 21S526(U) 121 Sentinel Radio H-838KU218 171 V-2323-101 17121TS17 8921TU14 89

Packard -Bell

21S537(U) 121215548(U) 1212135251(U) 1212155252(U) 121243529,-U 115245531,-U 115

H -841T21 171H-841TU21 171H -842T21 171H-842TU21 171H -843K21 171H-843KU21 171

V-2323-201 171V-2323-301 171V-2324 171

Zenith Radio

1U-701 1371U-711 1371U-714 1371U-721 1371U-724 1371U-752 137

2842 932843 93 19M20 1792844 932940 932941 933 041 93

Philco Corp.

243532,-U 11524T420, -U 11524T435, -U 115KCS84C 115KCS84E 115KCS84F 115KCS84H 115KCS84J 115KCS84K 115KCS87 121KCS87A 121KCS88 121KCS88A 121KCSB8B to F 121KCS88H 121KCS88J to P 121KCS88V,-VA 121

1U-755 1371U-758 1371U-762 1371U-765 1371U-768 1371U-791 1371U-901 1431U-911 1431U-914 1431U-921 1431U-924 1431U-991 143

Spar ton

H -844K21 171H-844KU21 171H -847K21 171H-847KU21 171H -848K21 171H-848KU21 171H -853K24 171H-853KU24 171H -854K24 171H-854KU24 171H -861T21 171H-861TU21 171H -862T21 171H-862TU21 171H -863T21 171H-863TU21 171H -864T21 171H-864TU21 171

19M20Z 17919M21, -Z 17919R20 17919R21 17919R22 17920M20, -Z 17920M21, -Z 17922R20 17922R 21 179M1800+ 179R1800+ 179R1812+ 179M2228+ 179M2229+ 179R2229+ 179M2230+ 179R2230+ 179M2237+ 179

22C4010 9722C4010L 9722C4012 9722C4014 9722C4016 9722C4119 9722C4120 9722C4122 9722C4123 9722C4124 9722C4126 9722C4310 97

11T210 14712A204 14712A210 14714A204 147

22C4312 97 agytheon 23U214 147 H -865T21 171 M2249+ 17924C 6010 97 17T18 129 H-865TU21 171 R2249+ 17924C6109 97 21T19 129 Stewart -Warner H -866T21 171 M2250+ 17924C6110 97 M-1750 130 17T -9620A 151 H-866TU21 171 R2250+ 17924C6112 97 M-1751 130 17T -9620B 151 H -867T21 171 M2252+ 17924C6310 97 M-1752 130 21C-970OR 154 H-867TU21 171 R2253M 179TV -300 98 M-2160 130 21C-9700RB 154 H -868T21 171 R2257E,R 179TV -301 98 M-2161 130 21C -9700W 154 H-868TU21 171 R2258+ 179TV -350 107 M-2162 130 21C-9700WB 154 H -869K24 171 M2260+ 179TV -354 107 21C -9700X 154 H-869KU24 171 M2261+ 179

Sears, Roebuck 21C-9700XB 154 H -870K24 171 M2267+ 179RCA Victor 3102X 133 21T -9630A 151 H-870KU24 171 R2337E,R 179173450 121 3104A 133 21T-9630AB 151 H -871 T21 171 R2359E,R 179173451 121 3112X 133 21T -9630p 151 H-871TU21 171 R2360R 179173453 121 4108,-A 133 21T-9630CB 151 H -872T21 171 R2367E,Y 17921S348K(U) 121 4112 133 21T -9630D 151 H-872TU21 171 R2368R 17921S355K(U) 121 4113A, -B 133 H-875T24(A)171 R2387R 17921S357K(U) 121 4118B, -C 133 Stromberg- H-875TU24 171 R2391R 17921S362K(U) 121 4119A 133 Carison H -876T24 171 M2570R,RZ 17921S367K(U) 121 4125 133 21T 157 H-876TU24 171 R2671E,R 17921S369K(U) 121 4127C, -D 133 22T 157 H -877T24 171 R2975R 179213501(U) 121 4129A, -B 133 H-877TU24 171 R2976E 179218502(U) 121 4133 133 Sylvania Elect. H -878K24 171 R2979E 17921S503(U) 121 4135,-B 133 1-522-1,-2 161 H-878KU24 171 R2994EU 179213504(U) 121 4140E 133 596 161 H -881K24 171 R2994HU 179

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