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Sharp LC-20B4E Service Manual
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Sharp LC-20B4E Service Manual

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See also: Operating Manual
In the interests of user-safety (Required by safety regulations in some countries) the set should be restored
to its original condition and only parts identical to those specified should be used.
» IMPORTANT SERVICE SAFETY PRECAUTION ........................................................................................ 2
» SPECIFICATIONS ........................................................................................................................................ 4
» OPERATION MANUAL ................................................................................................................................. 5
» DIMENSIONS ............................................................................................................................................... 7
» REMOVING OF MAJOR PARTS .................................................................................................................. 8
» ADJUSTING PROCEDURE OF EACH SECTION ..................................................................................... 12
» TROUBLE SHOOTING TABLE ...................................................................................................................16
» CHASSIS LAYOUT .....................................................................................................................................22
» BLOCK DIAGRAM ......................................................................................................................................24
» OVERALL WIRING DIAGRAM ...................................................................................................................26
» DESCRIPTION OF SCHEMATIC DIAGRAM ............................................................................................. 28
» SCHEMATIC DIAGRAM ............................................................................................................................. 29
» PRINTED WIRING BOARD ASSEMBLIES ................................................................................................54
» REPLACEMENT PARTS LIST ....................................................................................................................66
» PACKING OF THE SET ..............................................................................................................................79
SERVICE MANUAL
LCD COLOUR TELEVISION
MODEL
CONTENTS
SHARP CORPORATION
LC-20B4E
LC-20B4E
S33Y8LC-20B4E
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Summary of Contents for Sharp LC-20B4E

  • Page 1: Table Of Contents

    LC-20B4E SERVICE MANUAL S33Y8LC-20B4E LCD COLOUR TELEVISION LC-20B4E MODEL In the interests of user-safety (Required by safety regulations in some countries) the set should be restored to its original condition and only parts identical to those specified should be used.

  • Page 2: Important Service Safety Precaution

    LC-20B4E IMPORTANT SERVICE SAFETY PRECAUTION Ë Service work should be performed only by qualified service technicians who are thoroughly familiar with all safety checks and the servicing guidelines which follow: • Use an AC voltmeter having with 5000 ohm per volt, or...
  • Page 3 LC-20B4E Precautions for using lead-free solder 1 Employing lead-free solder "All PWBs" of this model employs lead-free solder. The LF symbol indicates lead-free solder, and is attached on the PWBs and service manuals. The alphabetical character following LF shows the type of lead-free solder.

  • Page 4: Specifications

    LC-20B4E SPECIFICATIONS Item 20" LCD COLOUR TV LCD panel 20" Advanced Super View & BLACK TFT LCD Number of dots 921,600 dots Video colour system PAL/SECAM/NTSC TV-Standard (CCIR) B/G, I, D/K, L TV-Tuning System Auto preset 200 ch. STEREO/BILINGUAL NICAM, IGR...

  • Page 5: Operation Manual

    LC-20B4E OPERATION MANUAL...
  • Page 6 LC-20B4E...

  • Page 7: Dimensions

    LC-20B4E DIMENSIONS Unit: mm MENU TV/VIDEO 403.3 110.7 76.1 AV-IN 1 AV-IN 2 S-VIDEO VIDEO AUDIO OUT AUDIO POWER INPUT DC13V 30.5 182.4 249.6...

  • Page 8: Removing Of Major Parts

    LC-20B4E REMOVING OF MAJOR PARTS 1. Remove the stand fixing screws (4 pcs.). 2. Remove the two terminal covers. 3. Remove the terminal section fixing screws (2 pcs.). 4. Remove the cabinet B fixing screws (12 pcs.). 5. Remove the cabinet B after opening from the direction of an arrow.
  • Page 9 LC-20B4E 9. Remove the inverter-A PWB fixing screws (2 pcs.). 10.Remove the inverter-B PWB fixing screws (1 pc.). 11.Remove the main PWB fixing screws (3 pcs.). 12.Remove the 21-pin terminal fixing screw (2 pcs.). 13.Remove the tuner PWB fixing screws (3 pcs.) and detach the chassis frame cover fixing hooks.
  • Page 10 LC-20B4E » Precautions in handling the LCD panels 1. Work in a clean room (with humidities below 50%). 2. Be sure to wear an anti-static armband. 3. Handle the panels on an electro-conductive mat. 4. Be careful not to fall, shake and shock the panels.
  • Page 11 LC-20B4E »Precautions at the time of the side B(back) service of main unit. 1. Remove only SC2002 of the FFC for connection between Main unit(SC2002) and Tuner unit(SC3902), and con- nect the extended cable (QCNW-A369WJZZ) for service. 2. Peel off the tape.

  • Page 12: Adjusting Procedure Of Each Section

    LC-20B4E ADJUSTING PROCEDURE OF EACH SECTION The best adjustment is made before shipping. If any position deviation is found or after part replace is performed, adjust as follows. Preparation for adjustments Use the dedicated AC adaptor or stable DC power supply.
  • Page 13 LC-20B4E 4. Initialization When the microprocessor (IC2001) or the EEPROM (IC2008, IC2010) has been replaced or when the EEPROM has been initialized, readjust the each adjustments. 4-1. Connect the pins (81) and (82) of IC2001 (microprocessor) to GND, and turn on the power.
  • Page 14 LC-20B4E 5. Adjustment 5-1. +B adjustment...Page 1 +B-ADJ Adjust the voltage of the pin (4) of P1902 to 5.00 ±0.02V with R3714. Note: Since 5.0V is a reference voltage of all power voltage, adjust it precisely. 5-2. Counter-bias adjustment Vary the "COM BIAS" setting on Page 2 of the adjustment process mode so that the contrast be sharpest (black looks most sinking).
  • Page 15 LC-20B4E 6. Factory Setting 6-1. Perform a factory setting after completing all adjustments. 6-2. A “POWER” keys is made on with pushing an “TV/VIDEO” and “MENU” keys at the same time. 6-3. “K” of the inspection process mode is displayed on the screen upper left.

  • Page 16: Trouble Shooting Table

    LC-20B4E TROUBLE SHOOTING TABLE...
  • Page 17 LC-20B4E TROUBLE SHOOTING TABLE (Continued)
  • Page 18 LC-20B4E TROUBLE SHOOTING TABLE (Continued)
  • Page 19 LC-20B4E TROUBLE SHOOTING TABLE (Continued)
  • Page 20 LC-20B4E TROUBLE SHOOTING TABLE (Continued)
  • Page 21 LC-20B4E...

  • Page 22: Chassis Layout

    LC-20B4E CHASSIS LAYOUT OPERATION Unit MAIN Unit TUNER Unit R/C, LED Unit...
  • Page 23 LC-20B4E INVERTER-A Unit INVERTER-B Unit...

  • Page 24: Block Diagram

    LC-20B4E BLOCK DIAGRAM ANA_IN1+ SIF1 TUNER ANTENNA DACM_L/R AI_L/R SC2_IN_L/R SCART IC1901 AUDIO MAP DACA_L/R SC3901 SC1_OUT_L/R (AV1) SC1_IN_L/R SC_L/RO IC1902 AUDIO IN TV_V SC2_OUT_L/ AUDIO OUT VIDEO OUT TV/AV CVBS/SY_IN SDA/RXD IC808 SELECTOR V1.SY R/G/B_IN SCL/TXD IC801 IC806 SC_IN...
  • Page 25 LC-20B4E AUDIO ACTIVE FILTER L/R_IN AUDIO P3301 SPEAKER CM_L/R POWER AMP FLSP/FRSP IC1905 P3302 IC3301 AUDIO AMP CA_L/R J5002 IC304 HEADPHONE HL/R AUDIO AMP AO_L/R JACK SC2_OUT_L/R IC3501 PAVCC(+13V) J3901 AUDIO OUT VPC0∼7 YIN0∼7 SYNC SIGNAL R0∼7 G0∼7 B0∼7 SC1202...

  • Page 26: Overall Wiring Diagram

    LC-20B4E OVERALL WIRING DIAGRAM...
  • Page 27 LC-20B4E...

  • Page 28: Description Of Schematic Diagram

    LC-20B4E DESCRIPTION OF SCHEMATIC DIAGRAM VOLTAGE MEASUREMENT CONDITION: 1. The voltages at test points are measured on exclusive AC adaptor and the stable supply voltage of AC 120V. Signals are fed by a color bar signal generator for servicing purpose and the above voltages are measured with a 20k ohm/V tester.

  • Page 29: Schematic Diagram

    LC-20B4E SCHEMATIC DIAGRAM Ë R/C, LED and OPERATION Unit...
  • Page 30 LC-20B4E Ë MAIN Unit-1/7...
  • Page 31 LC-20B4E...
  • Page 32 LC-20B4E Ë MAIN Unit-2/7...
  • Page 33 LC-20B4E...
  • Page 34 LC-20B4E Ë MAIN Unit-3/7...
  • Page 35 LC-20B4E...
  • Page 36 LC-20B4E Ë MAIN Unit-4/7...
  • Page 37 LC-20B4E...
  • Page 38 LC-20B4E Ë MAIN Unit-5/7...
  • Page 39 LC-20B4E...
  • Page 40 LC-20B4E Ë MAIN Unit-6/7...
  • Page 41 LC-20B4E...
  • Page 42 LC-20B4E Ë MAIN Unit-7/7...
  • Page 43 LC-20B4E...
  • Page 44 LC-20B4E Ë TUNER Unit-1/4...
  • Page 45 LC-20B4E...
  • Page 46 LC-20B4E Ë TUNER Unit-2/4...
  • Page 47 LC-20B4E...
  • Page 48 LC-20B4E Ë TUNER Unit-3/4...
  • Page 49 LC-20B4E...
  • Page 50 LC-20B4E Ë TUNER Unit-4/4...
  • Page 51 LC-20B4E...
  • Page 52 LC-20B4E Ë INVERTER-A Unit...
  • Page 53 LC-20B4E Ë INVERTER-B Unit...

  • Page 54: Printed Wiring Board Assemblies

    LC-20B4E PRINTED WIRING BOARD ASSEMBLIES MAIN Unit (Side-A)
  • Page 55 LC-20B4E TP2041 SC1204 C1227 C1228 C1229 C1230 C1231 C1232 C1233 R837 R841 R836 C851 C852 R1233 R1231 R1258 C853 IC801 R847 R832 R833 R844 R1224 C875 R845 C835 R875 L808 L806 R827 C1204 C1205 C1206 C1207 C1208 C872 R1217 R1216...
  • Page 56 LC-20B4E MAIN Unit (Side-B)
  • Page 57 LC-20B4E R1245 C1239 R1243 C1241 R1248 C830 R7006 R830 C810 R815 C821 C815 R817 Q804 C823 R824 R1249 D1201 C828 D1202 IC808 D1204 R829 D1203 R871 C832 R1250 C801 R1255 C802 D1206 Q1210 C1238 C805 D1205 IC1202 R859 R865 IC803...
  • Page 58 LC-20B4E R/C, LED Unit (Side-A) D4022 R4023 Q4001 D4012 Q4007 SLD4001 R4024 RMC4002 D4014 D4011 R4029 R/C, LED Unit (Chip Parts Side-A) OPERATION Unit (Side-A) (QPWBSB753WJN2) S4701 OPERATION Unit (Chip Parts Side-A) (QPWBSB753WJN2)
  • Page 59 LC-20B4E TUNER Unit (Side-A)
  • Page 60 LC-20B4E TP3701 P3604 P3603 R3310 C3304 P3902 C3306 C3305 D3302 R3304 R3311 C3307 R3306 D3301 R3302 Q3301 C3316 R3305 R3307 C3308 C3311 FH3304 FH3302 R3309 R3308 R3312 C3309 C3302 C3301 R3318 D3702 C3706 R3713 Q3703 FH3303 FH3301 C3709 R3721 R3715...
  • Page 61 LC-20B4E P3301 P3602 P3302 P3601 C3305 C3307 R3605 R3601 J5002 Q3302 R3603 C3610 D3604 R3313 R3602 C3311 C5002 R3610 Q3605 C3604 C3608 R3606 Q3602 C3315 C3309 D3607 D3606 Q3604 R3607 FB5002 D3608 C3607 FB5001 R3609 R5007 Q3901 R3721 R3715 C3314...
  • Page 62 LC-20B4E INVERTER-A Unit (Side-A)
  • Page 63 LC-20B4E R6722 Q6706 C6712 C6713 T6705 R6710 Q6707 R6727 C6727 D6700 R6705 R6726 R6725 Q6704 R6721 Q6703 R6707 C6708 T6704 R6706 R6704 FH6701 FH6700 T6703 T6702 Q6701 C6702 R6720 Q6702 Q6700 T6701 T6700 INVERTER-A Unit (Chip Parts Side-A)
  • Page 64 LC-20B4E INVERTER-B Unit (Side-A)
  • Page 65 LC-20B4E T6709 T6708 R6716 T6707 Q6714 R6724 C6740 T6706 D6701 R6715 C6718 R6714 FH6707 FH6706 INVERTER-B Unit (Chip Parts Side-A)

  • Page 66: Replacement Parts List

    LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code PARTS LIST IC1605 VHiMM1562FF-1Y J MM1562FFBE IC1606 VHiPST3221N1EY J PST3221NR PARTS REPLACEMENT IC1607 VHiMM1563DF-1Y J MM1563DFBE IC1608 VHiNC7SZ58P-1Y J NC7SZ58P6X IC1609 VHiTC7SZ08U-1Y J TC7SZ08FU Replacement parts which have these special safety characteristics...
  • Page 67 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB750FE03 C831 RC-KZ1025CEZZY Ceramic C832 VCKYCY1EF104ZY J 0.1 Ceramic MAIN UNIT (Continued) C833 RC-EZA123WJZZY J 100 6.3V Electrolytic C835 VCKYCY1HB331KY J 330p Ceramic FILTER AND COILS C836...
  • Page 68 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB750FE03 C2018 VCKYTV1CF684ZY J 0.68 Ceramic C2020 RC-EZA124WJZZY J 10 Electrolytic MAIN UNIT (Continued) C2022 VCKYCY1EF104ZY J 0.1 Ceramic C2023 VCKYCY1EF104ZY J 0.1 Ceramic C1227 VCKYCY1EF104ZY J 0.1 Ceramic C2024 VCKYCY1EF104ZY J 0.1...
  • Page 69 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB750FE03 R1627 VRS-CY1JF333JY J 33k 1/16W Metal Oxide R1628 VRS-CY1JF332JY J 3.3k 1/16W Metal Oxide MAIN UNIT (Continued) R1629 VRS-CY1JF332JY J 3.3k 1/16W Metal Oxide R1631 VRS-CY1JF222JY J 2.2k 1/16W Metal Oxide...
  • Page 70 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB750FE03 DUNTKB751DE03 MAIN UNIT (Continued) TUNER UNIT TUNER R2080 VRS-CY1JF472JY J 4.7k 1/16W Metal Oxide R2081 VRS-CY1JF101JY J 100 1/16W Metal Oxide NOTE: THE PARTS HERE SHOWN ARE SUPPLIED AS AN...
  • Page 71 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB751DE03 C1917 RC-EZ0417CEZZY J 150 Electrolytic C1918 VCKYCY1HB102KY J 1000p 50V Ceramic TUNER UNIT (Continued) C1919 VCKYCY1EF104ZY J 0.1 Ceramic C1920 RC-EZA130WJZZY J 3.3 Electrolytic D3702 VHDDAN222//-1Y...
  • Page 72 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB751DE03 RESISTORS R345 VRS-CY1JF000JY 1/16W Metal Oxide TUNER UNIT (Continued) R346 VRS-CY1JF000JY 1/16W Metal Oxide R350 VRS-CY1JF392JY J 3.9k 1/16W Metal Oxide C3502 VCKYCY1EB223KY J 0.022 25V...
  • Page 73 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB751DE03 R3741 VRS-CY1JF122FY J 1.2k 1/16W Metal Oxide R3742 VRS-CY1JF682FY J 6.8k 1/16W Metal Oxide TUNER UNIT (Continued) R3743 VRS-CY1JF122FY J 1.2k 1/16W Metal Oxide R3744 VRS-CY1JF243FY...

  • Page 74: Operation Unit

    LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB751DE03 DUNTKB752DE03 TUNER UNIT (Continued) R/C, LED UNIT TRANSISTORS FB3705 RBLN-0051TAZZY J Ferrite Bead FB3707 RBLN-0254TAZZY J Ferrite Bead Q4001 VSDTC144EE/-1Y J DTC144EE FB3708 RBLN-0051TAZZY J Ferrite Bead...
  • Page 75 LC-20B4E Ref. No. Part No. Description Code Ref. No. Part No. Description Code DUNTKB590DE02 DUNTKB591DE02 INVERTER-A UNIT INVERTER-B UNIT TRANSISTORS TRANSISTORS Q6700 VS2SC5886++-1Y J 2SC5886 Q6709 VS2SC5886++-1Y J 2SC5886 Q6701 VS2SC5886++-1Y J 2SC5886 Q6710 VS2SC5886++-1Y J 2SC5886 Q6702 VS2SA1530AR-1Y J 2SA1530AR...
  • Page 76 LC-20B4E CABINET AND MECHANICAL PARTS OPERATION PWB INVERTER-A PWB 1-10 1-14 MAIN PWB 1-11 1-13 INVERTER-B 1-10 1-14 1-13 1-12 R/C, LED PWB TUNER PWB 5-2-1 5-18 5-2-3 5-19 5-10 5-2-2 5-14 5-15 5-16 5-20 5-13 5-12 5-18 5-17 5-11...
  • Page 77 J Stand Ass’y XEBSD30P08000 J Screw, x7 GDAi-A045WJSA J Stand, Base XEBSF40P16000 J Screw, x12 CDAi-1123CE01 J Stand Joint Ass’y TLABS0106TAZZ J GOST Label (LC-20B4E(R)) AD Not Available 3-2-1 – Stand Joint — 3-2-2 PSPAZA083WJZZ J Spacer, x2 GCOVA1945CESA J Stand Grip...

  • Page 78: Packing Parts

    Code PACKING PARTS ACCESSORIES (NOT REPLACEMENT ITEM) LHLDWA002WJSA J Cable Clamp, x2 SPAKCA538WJZZ – Packing Case — QACCKA006WJPZ J AC Cord (LC-20B4E/E(R)) SPAKFA320WJZZ – Buffer Material — å QACCBA016WJPZ J AC Cord (LC-20B4E(K)) (Accessories) å RRMCGA074WJSA J Infrared R/C Unit SPAKPA001WJZZ –...

  • Page 79: Packing Of The Set

    LC-20B4E PACKING OF THE SET Operation Manual (TiNS-A593WJZZ:LC-20B4E/E (TiNS-A670WJZZ:LC-20B4E Polyethylene Bag Cable Clamp (2pcs) (SSAKA0170CEZZ) (LHLDWA002WJSA) Guarantee card (TGAN-1688CEN1:LC-20B4E (TGAN-A077WJZZ:LC-20B4E AC Cord "AAA" size Battery (2pcs) (QACCKA006WJPZ:LC-20B4E/E (QACCBA016WJPZ:LC-20B4E AC Adapter Wrapping Paper (UADP-0241CEPZ) (SPAKPA001WJZZ) Infrared R/C Unit (RRMCGA074WJSA) Buffer Material (Accessories)
  • Page 80 LC-20B4E COPYRIGHT © 2003 BY SHARP CORPORATION ALL RIGHTS RESERVED. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher.

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