Sharp 37GQ-20H Service Manual
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Sharp 37GQ-20H Service Manual

Sharp 37GQ-20H Service Manual

Pal system colour television
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ELECTRICAL SPECIFICATION.......................2
IMPORTANT SERVICE NOTES.......................3
PRINTED WIRING BOARDS...........................11

SHARP CORPORATION

SERVICE MANUAL

PAL SYSTEM COLOUR TELEVISION
37GQ-20H
MODEL
In the interests of user safety (required by safety
regulations in some countries) the set should restored
to its original condition and only parts identical to
those specified should be used.
CONTENTS
PART LIST.......................................................18
TROUBLESHOOTING TABLES......................22
1
37GQ-20H
SEJB37GQ20H02
Issued: 9th June '00
SQUAD
CHASSIS
This document has been published to
be used for after sales service only.

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  • Page 1: Table Of Contents

    37GQ-20H SERVICE MANUAL SEJB37GQ20H02 Issued: 9th June ‘00 SQUAD CHASSIS PAL SYSTEM COLOUR TELEVISION 37GQ-20H MODEL In the interests of user safety (required by safety regulations in some countries) the set should restored to its original condition and only parts identical to those specified should be used.

  • Page 2: Important Service Notes

    37GQ-20H IMPORTANT SERVICE NOTES Maintenance and repair of this receiver should be done by qualified service personnel only. SERVICING OF HIGH VOLTAGE SYSTEM AND PICTURE TUBE When servicing the high voltage system, remove static charge from it by connecting a 10K ohm resistor in series with an insulated wire (such as test probe) between picture tube ground tag and high voltage lead.

  • Page 3: Service Adjustment

    37GQ-20H SERVICE ADJUSTMENT •SERVICE MODE FUNCTION This mode funtion is provided to assist with the settings of those adjustments that may vary from one Picture Tube to another, or between models. In order to use the Service Mode 1. Press main switch to OFF.
  • Page 4 37GQ-20H Bear in mind that, for storage location indication a hexadecimal numerical system is used, instead of a decimal system. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, 10, 11, ..19, 1A, 1B, 1C, 1D, 1E, 1F, 20, 21, .., 99, 9A, 9B, 9C, 9D, 9E, 9F, A0, A1, .., B0, .., C0, .., D0, ..E0, .., F0, F1, F2, F3, F4, F5, F6, F7, F8, F9, FA,...
  • Page 5 37GQ-20H ONE CHIP REGISTER 00: ONE CHIP REGISTER 01: ONE CHIP REGISTER 02: ONE CHIP REGISTER 03: ONE CHIP REGISTER 04: ONE CHIP REGISTER 05: ONE CHIP REGISTER 06: ONE CHIP REGISTER 07: ONE CHIP REGISTER 08: ONE CHIP REGISTER 09:...
  • Page 6 37GQ-20H VH F1HIGH : U PPER WIND OW LIM IT FOR V HF1 PRG _NUM B ER: CU RREN T PRO GRA M ME NU MBE R W AITSUP : U PPER L IM IT DE LAY TIME FOR A UTO SEAR CH.
  • Page 7 37GQ-20H VHF1_SP: STEP FOR AUTO SEARCH IN VHF1 BAND VHF3_SP: STEP FOR AUTO SEARCH IN VHF3 BAND UHF_SP: STEP FOR AUTO SEARCH IN VHF BAND OLD_PROGRAM: FOR FLASHBACK RETURN UHFHIGH: UPPER WINDOW LIMIT FOR UHF VHF3HIGH: UPPER WINDOW LIMIT FOR VHF3...
  • Page 8 37GQ-20H BG _COA RSE: TH IC K TU NING AD JU STM ENT FOR L AN D BG BG _FIN E: FIN E TU NING AD JU STM ENT FOR L AN D BG LP_FINE : FINE TUN IN G A DJUST ME NT FO R L’...
  • Page 9 37GQ-20H •GEOMETRY ADJUSTMENT PROCEDURE 1. HOR POS a) Receive Philips pattern signal. ∧ b) When button is pressed, picture moves to the left. ∨ c) When button is pressed, picture moves to the right. d) Adjust the horizontal location to obtain picture centering (Fig.1).

  • Page 10: Printed Wiring Boards

    37GQ-20H...
  • Page 11 37GQ-20H...

  • Page 12: Schematic Diagram, Wave Forms

    37GQ-20H DESCRIPTION OF SCHEMATIC DIAGRAM NOTE: SAFETY NOTE: 1. The unit of resistance «ohm»is omitted (K=1000 1. DISCONNECT THE AC PLUG FROM THE AC ohms. M= Megaohm). OUTLET BEFORE REPLACING PARTS. 2. All resistors are 1/8 watt. unless otherwise noted.
  • Page 13 37GQ-20H Page 16...
  • Page 14 37GQ-20H Page 17 SCHEMATIC DIAGRAM (01 Version).
  • Page 15 37GQ-20H SCHEMATIC DIAGRAM (01 Version).
  • Page 16 37GQ-20H SCHEMATIC DIAGRAM (01 Version). R OUT R IN L OUT L IN V OUT V IN...

  • Page 17: Part List

    37GQ-20H REF No. PARTS DESCRIPTION * CODE PART LIST Q 0708 VS2SC2412KQ-1 TRT 2SC2412 ROHM S AA Q 1001 RH-TX0111BMZZ TRT PH-2369 PHILIPS S AB REPLACEMENT PARTS Q 1002 VS2SC2412KQ-1 TRT 2SC2412 ROHM S AA Replacement parts which have special safety characteristics are identi-...
  • Page 18 37GQ-20H REF No. PARTS DESCRIPTION * CODE REF No. PARTS DESCRIPTION * CODE L 0801 VP-DF3R3K0000 PEAK COIL 3,3UH 10% S AA C 0709 RC-KZ0160BMZZ CERAM C 2,2NF 4KV X1Y1 S AC C 0710 VCEAGA1EW227M ELEC C 220UF 20% 25V...
  • Page 19 37GQ-20H REF NoPARTS DESCRIPTION * CODE REF No PARTS DESCRIPTION * CODE R 0310 VRS-TV1JD101J 2125 100 OHM 5% 1/10W SMD S AA R 0706 VRS-TV1JD681J 2125 680 OHM 5% 1/10W SMD S AA R 0311 VRS-TV1JD104J 2125 100KOHM 5% 1/10W SMD...
  • Page 20 37GQ-20H REF No PARTS DESCRIPTION * CODE REF No PARTS DESCRIPTION * CODE R 1028 VRD-RA2BE101J RES 100 OHM 5% 1/8W S AA C 0878 VCEAGA2DW106M ELEC C 10UF 20% 200V S AC R 1029 VRD-RA2BE101J RES 100 OHM 5% 1/8W...

  • Page 21: Troubleshooting Tables

    37GQ-20H TROUBLESHOOTING TABLES. NO PICTURE Check Picture setting by R/C. Signal should be received. Check the tuner supply and band biases. Both must be approx. 5V DC Normal Is tuning voltage normal at Pin (2) of Tuner? Check Q1001, IC1001, IC1003 -Check the AGC Voltage: Pin (1) of Tuner.
  • Page 22 37GQ-20H NO SOUND Check Sound setting by R/C. Signal should be received. Does approx. 20V DC appear on C710? Check D707, C710 Does Sound Signal appear at Pin(6) of IC801? Check IC801, C301 Audio Amplifier muted? Check IC1001, Q305 Check R304, Q301, Q302...
  • Page 23 37GQ-20H NO RASTER Fuse Blown Check F701 Normal Check Voltage on C705 Replace Fuse (Approx. 325V DC) Fuse Blown Normal again Check Voltage on C711 Check IC701 Approx. 0V Abnormal (Approx. 105V DC) Normal Normal Check D708, D717 Check CRT connector K1...
  • Page 24 37GQ-20H NO VERTICAL SCAN Is IC501 bias normal? Check R510, Q501, Check D709, D710, IC501 Q502, Q503 NEITHER VERTICAL NOR HORIZONTAL SYNCHRONIZATION Check IC801, C815, C816, R818 DEFECTIVE VERTICAL AMP. AND VERTICAL LINEARITY Readjust Vertical Size. Vertical size is abnormal...
  • Page 25 37GQ-20H NO SPECIFIC COLOUR some colour produced in B/W Broadcast reception? Check IC801, C812, C813, R813, X801 the white balance properly adjusted? The Picture Colour is The Picture Colour is The Picture Colour is Red or cyan. green or magenta.
  • Page 26 37GQ-20H NOTES:...
  • Page 27 37GQ-20FP RECICLED PAPER PRINTED BY:...

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