LC-20B4M SERVICE MANUAL S43A4LC-20B4M LCD COLOUR TELEVISION MODEL LC-20B4M 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. CONTENTS Page » » » » » » » » » » » » » » » IMPORTANT SERVICE SAFETY PRECAUTION ........................................................................................ 2 SPECIFICATIONS ................................................
LC-20B4M 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 higher, sensitivity or measure the AC voltage drop across the resistor.
LC-20B4M 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. Example: LFa Indicates lead-free solder of tin, silver and copper. 2 Using lead-free wire solder When fixing the PWB soldered with the lead-free solder, apply lead-free wire solder.
LC-20B4M SPECIFICATIONS MODEL ITEMS LC-20B4M LCD panel 19.7" (50 cm) Advanced Super View & BLACK TFT LCD Number of dots 921,600 dots VGA Video colour systems World multi system TV Standard I/DK/M/BG TV Tuning System Auto preset tuning TV STEREO/BILINGUAL NICAM-BG, I, DK/IGR-BG FUNCTION Universal R/C for TV only Yes AUTO PRESET Yes CATV S1~S41 ch. Hyper Band 4-LINE DIGITAL COMB FILTER Yes Brightness 430 cd/m2 Lamp life 60,000 hours Viewing angles H: 170° V: 170° Audio output 2.
POWER SLEEP To change the vertical angle of the LCD TV set, tilt the screen up to 5 degrees forward or 10 degrees backward. The TV set can also be rotated 25 degrees to right and left. Please adjust the angle so that the TV set can be watched most comfortably. A green indicator lights when the power is on and a red indicator lights when in the standby mode (the indicator will not light when the main power is off).
POWER BRIGHT WIDE TEXT TEXT 6 DIS.MODE SLEEP Flashback Returns to the previous channel. CHANNEL SELECT VOL (+)/(-) Green Red Right / Left Selection MPX Switches Audio mode. SUBTITLE Displays the Teletext Subtitle directly. MENU Displays the TV menu. SLEEP VOL MPX SOUND SUBTITLE LE SUBTIT DIS.MODE CH MENU TATE TV/ RO VIDEO E END END TV/VIDEO M OK MENU HOLDLD SUBPAGE SUBPAGE RE REVEAL VEAL HO T DISPLAY Press....Displays receiving channel for 10 seconds.
LC-20B4M DIMENSIONS CH 2 T MENU V/VIDEO MAIN POWER 68.6 VOL PRESET 1 420 193.5 471.5 300.8 381.5 188 630 403.3 POWER SLEEP 110.7 76.1 VIDEO AV-IN1 AV-IN 2/OUT L AUDIO L 100 51.5 VIDEO AUDIO R S-VIDEO R HEAD PHONE COMPONENT 470.3 Y PB ANT. PR 100 L AUDIO USE THE SUPPLIED AC ADAPTER. (PART NO. LOCATED ON THE MODEL LABEL.) POWER INPUT DC13V R 249.6 7 76.
LC-20B4M 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. 6. Remove the reinforcement angle fixing screws (4 pcs.). 7. Release peel off the tape. 4 8. Detach the connector from each PWB.
LC-20B4M 9. Remove the inverter-A PWB fixing screws (2 pcs.). 10. Remove the inverter-B PWB fixing screw (1 pc.). 11. Remove the main PWB fixing screws (3 pcs.). 12. Remove the tuner PWB fixing screws (3 pcs.) and detach the chassis frame cover fixing hooks. 13. Remove the R/C, LED PWB fixing screws (2 pcs.). 14. Remove the operation PWB fixing screws (2 pcs.).
LC-20B4M » 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. 15. Remove the LCD panel unit fixing screws (4 pcs.). 16. Remove the ITO earth spring fixing screw (1 pc.). 17. Remove the reflection/deflection, prism, diffusion, ITO sheets and diffusion panel. 18. Remove the lamp fixing holder fixing screws (6 pcs.). 19.
LC-20B4M Precautions at the time of the side B(back) service of digital unit. 1. Remove only SC2002 of the FFC for connection between Main unit (SC2002) and Tuner unit(SC3403), and connect the extended cable (QCNW-A556WJZZ) for service. 2. Remove the FFC for connection between Main unit (SC1204) and LCD panel unit, and connect the extended cable (QCNW-A553WJZZ) for service. 3.
LC-20B4M 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 exclusive-use AC adapter or stable DC power supply. AC adapter: UADP-0241CEPZ DC power supply: 13 ± 0.5V 5.4A 1. Adjustment Procedure 1-1.
LC-20B4M 5. Adjustment 5-1. +B adjustment (R3714 Variable resistor) 1) Receive the colour bar signal. 2) Adjust the voltage at pin (4) of P3701 to 5.00 ± 0.02 V. Note: The 5.0 V level is used as reference for all the line voltages. Make this adjustment as precisely as possible. 5-2. Counter bias adjustment: COM BIAS on page 2 Adjust the "COM BIAS" setting until the contrast gets optimum (the black portion blackest). The adjustment guideline is around 98. 5-3.
LC-20B4M 5-5. Other adjustments (SOUND, VPC, DPS, DAC, TUNER, OTHERS, TEXT) 1) Move the cursor to a desired item on page 4 of adjustment process menu. Press the CURSOR LEFT/ RIGHT keys, "VOL (+)/(–)" keys or OK key to select the item. 4 I2C DATA 000000000000 I2C DATA WAIT SOUND VPC DPS DAC TUNER OTHERS TEXT 2) The adjustment process menu of the item appears on the screen. The settings are now ready to change.
LC-20B4M 6. Lamp error detection 6-1. Functional description This LCD colour television has a function (lamp error detection) to be turned OFF automatically for safety when the lamp or lamp circuit is abnormal. If the lamp or lamp circuit is abnormal, or some other errors happen, and the lamp error detection is executed, the followings occur. 1 The main unit of television is turned OFF 5 seconds after it is turned ON. (The power LED on the front side of TV turns from green to red.
LC-20B4M 7. Public mode • How to enter into PUBLIC MODE 1. Turn off TV by pressing MAIN POWER switch. 2. While pressing "VOL(+)" key and "CH(ù)" key at the same time, press MAIN POWER switch for more than 2 seconds. TV will turn on, and you will see the screen display a setting of PUBLIC MODE.
LC-20B4M 8. SOUND ONLY MODE (NO↔YES) (* This item cannot be selected if "NO" appears on the on-screen display.) Let's suppose that this item has been selected and the BRIGHT key on the remote control has been pressed. The item "BRIGHTNESS [OFF]" can now be selected next to the item "BRIGHTNESS [DARK]". Screen with "BRIGHTNESS [OFF]" selected Count-down started from 5 BRIGHTNESS [OFF] TURNS OFF IN 5 SECS. Five seconds later, the screen shuts off and the sound alone is heard.
LC-20B4M TROUBLE SHOOTING TABLE No or Wrong Picture Does the IC801 test pattern appear properly? No Yes Does the IC1201 test pattern appear properly? Yes No Check the IC801 signal output line, IC801 itself and its peripheral circuits. Are the waveforms at pins (8), (9), (26), and (27) of IC1201 as specified? Yes No Check IC1201 and its peripheral circuits as well as the LCD panel voltage and waveform.
Are inputs and outputs of IC801 as specified? Yes No Does the video decoder No test pattern appear? Yes Does the DPS No test pattern appear? No picture at all Check IC3401 and its peripheral parts. Check IC801 and its peripheral circuits. Check IC1201, its peripheral circuits and the LCD panel. No Check IC3401 and its peripheral parts.
No No TV colour Check the secondary-side load of T3701. Yes Are the oscillation waveform at T3701’s primary side as specified? No Are secondary outputs (+38V, +9V, +5V, -11V) of T3701 as specified? Yes Do F3701 and F3702 function? No picture and sound No No No No S-VIDEO colour Check SC3405, SC line and peripheral parts. No Is input at Pin (72) of IC801 as specified? Check Q6700 - 6714, T6700 - 6709 and their peripheral parts. Yes Check the line, IC1201 and its peripheral parts.
Check the speakers and their peripheral parts. Yes Are inputs at Pins (2) and (4) as well as outputs at Pins (8) and (12), all of IC3305, as specified? Yes Are outputs at Pins (1) and (7) of IC3301/ IC3303 as specified? Yes Are input and output of IC3304 as specified? Yes Is Pin (53) of IC2001 at “L”? No sound from speakers No No No No Check the line in question, IC3301 and its peripheral parts. Check IC3301, IC3303 and their peripheral parts. Check IC3304 and its peripheral parts.
LC-20B4M CHASSIS LAYOUT OPERATION Unit H MAIN Unit G F E TUNER Unit D C B R/C, LED Unit A 1 2 3 4 5 6 22 7 8 9 10
LC-20B4M INVERTER-A Unit INVERTER-B Unit 10 11 12 13 14 15 23 16 17 18 19
LC-20B4M BLOCK DIAGRAM SC3403 AGC,AFT,SAW_ SW,MODE 1 ,MODE 2 SC H TV_ V TUNER TU3201 SIF SIF AMP Q3201 ,Q3202 F F F F V1 _ V AV1 _ L,R AV1 INPUT G S-VIDEO SY VIDEO SC SWITCH V_IN IC3401 INPUT AMP IC3502 V2_V IN/OUT F SSTBY AV2 INPUT/OUTPUT AV2_L,R IN/OUT AUDIO IN/OUT VIDEO IN/OUT SWITCH SWITCH IC3501,Q3501 Q3502-Q3505 AV2_R,L SC1_OUT_R,L COMPONENT V_IN/OUT S_IN/OUT Y,PB,PR INPUT AUDIO DL,DR DECODER E OFL REVERSE (MSP) OFL1 Q3601 OFL IC3304 P3501 L_ERR RXD,TXD LA
LC-20B4M 403 SC2002 I2C LCD CONTROLLER R0~7,G0~7,B0~7 (DPS) V0,V7,V21 IC1201 V64,V112 REV V176 ,V235 GRADATION V255 POWER VCOM IC1101 VIDEO DECODER (VPC) IC801 FILTER FL801 FILTER FL802 V2V0 SYNC SEP IC802 LCD PANEL CSCOM CSYNC OSD R/G/B VLS,VGL,VEE I2C GSP1,VSH GBLR,GCK POWER E2 PROM GSP2 IC2010 MICON TX_FB IC2001 RESET IC2006 TEXT R/G/B TEXT R/G/B AMP RXD,TXD Q1602,Q1604,Q1606 L1 TELETEXT SRAM 2M CPU IC1612 IC1601 FLASH 4M VIDEO SW IC1604 SWITCH RX_TX,TX_RX IC1611 IC2003 3
LC-20B4M OVERALL WIRING DIAGRAM H G F E D C B A 1 2 3 4 5 6 26 7 8 9 10
LC-20B4M 10 11 12 13 14 15 27 16 17 18 19
LC-20B4M 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. INDICATION OF RESISTOR & CAPACITOR: RESISTOR 1. The unit of resistance “Ω” is omitted. (K=kΩ=1000 Ω, M=MΩ). 2. All resistors are ± 5%, unless otherwise noted. (J= ± 5%, F= ± 1%, D= ± 0.5%) 3.
LC-20B4M SCHEMATIC DIAGRAM Ë R/C, LED and OPERATION Unit H G F E D C B A 1 2 3 4 29 5 6
LC-20B4M Ë MAIN Unit-1/7 H G F E D C B A 1 2 3 4 5 6 30 7 8 9 10
LC-20B4M 10 11 12 13 14 15 31 16 17 18 19
LC-20B4M Ë MAIN Unit-2/7 H G F E D C B A 1 2 3 4 5 6 32 7 8 9 10
LC-20B4M 10 11 12 13 14 15 33 16 17 18 19
LC-20B4M Ë MAIN Unit-3/7 H G F E D C B A 1 2 3 4 5 6 34 7 8 9 10
LC-20B4M 10 11 12 13 14 15 35 16 17 18 19
LC-20B4M Ë MAIN Unit-4/7 H G F E D C B A 1 2 3 4 5 6 36 7 8 9 10
LC-20B4M 10 11 12 13 14 15 37 16 17 18 19
LC-20B4M Ë MAIN Unit-5/7 H G F E D C B A 1 2 3 4 5 6 38 7 8 9 10
LC-20B4M 10 11 12 13 14 15 39 16 17 18 19
LC-20B4M Ë MAIN Unit-6/7 H G F E D C B A 1 2 3 4 5 6 40 7 8 9 10
LC-20B4M 10 11 12 13 14 15 41 16 17 18 19
LC-20B4M Ë MAIN Unit-7/7 H G F E D C B A 1 2 3 4 5 6 42 7 8 9 10
LC-20B4M 10 11 12 13 14 15 43 16 17 18 19
LC-20B4M Ë TUNER Unit-1/4 (LC-20B4M) H G F E D C B A 1 2 3 4 5 6 44 7 8 9 10
LC-20B4M 10 11 12 13 14 15 45 16 17 18 19
LC-20B4M Ë TUNER Unit-1/4 (LC-20B4M(X)) H G F E D C B A 1 2 3 4 5 6 46 7 8 9 10
LC-20B4M 10 11 12 13 14 15 47 16 17 18 19
LC-20B4M Ë TUNER Unit-2/4 H G F E D C B A 1 2 3 4 5 6 48 7 8 9 10
LC-20B4M 10 11 12 13 14 15 49 16 17 18 19
LC-20B4M Ë TUNER Unit-3/4 H G F E D C B A 1 2 3 4 5 6 50 7 8 9 10
LC-20B4M 10 11 12 13 14 15 51 16 17 18 19
LC-20B4M Ë TUNER Unit-4/4 H G F E D C B A 1 2 3 4 5 6 52 7 8 9 10
LC-20B4M 10 11 12 13 14 15 53 16 17 18 19
LC-20B4M Ë INVERTER-A Unit H G F E D C B A 1 2 3 4 54 5 6
LC-20B4M Ë INVERTER-B Unit H G F E D C B A 1 2 3 4 55 5 6
LC-20B4M PRINTED WIRING BOARD ASSEMBLIES H G F E D C B A MAIN Unit (Side-A) 1 2 3 4 56 5 6
LC-20B4M H R1235 R1242 R1241 R1240 R1234 R1239 R1238 C1226 C1225 C1224 C1223 C1222 R1232 C1220 R1228 C1218 C1217 R1227 C1215 FB1201 R1225 R1226 C1214 C1211 C1210 C1209 R1222 X1201 C1213 C1212 R1223 R1221 R1262 R827 SC1203 IC1201 C1216 R1211 R1220 R1212 R1219 R1260 R1218 R1215 R1210 R1214 R1213 C1236 C1243 L1204 C1234 R1120 SC1202 C1244 R1116 D1104 C1104 L1206 R1101 L1207 C722 C1245 C1106 C1107 IC1101 C1101 C1110 C1109 C1102 R1103 R1102 C1108 C1105 C726 IC702 C711
LC-20B4M H G F E D C B A MAIN Unit (Side-B) 1 2 3 4 58 5 6
1 2 3 59 4 5 D2001 IC1610 R2096 R2055 R2041 R704 Q2006 R2087 R2090 Q2005 TL712 TL710 D710 IC706 TL713 TL711 TL801 R863 C834 R804 R870 C871 C870 R861 R824 R2099 C2004 IC2003 Q808 R864 R852 IC806 C803 C823 R820 C831 C814 C810 TL2036 R706 TL2032 C704 TL707 TL705 TL703 TL709 TL704 TL708 TL706 TL702 D704 TL2034 C2028 TL2058 IC2011 TL2057 D702 R2080 C721 R2045 C710 R2014 C2008 C861 R851 R806 C804 TL1283 D1203 TL2030 Q2002 R2043 C869 C868 C867 C860 R85
LC-20B4M H R/C, LED Unit (Side-A) R4021 C4018 G R4023 SLD4001 D4015 P4004 D4012 R4024 R4029 RMC4002 Q4001 Q4007 R4001 Q4003 D4022 D4014 D4011 F R/C, LED Unit (Chip Parts Side-A) E D OPERATION Unit (Side-A) (QPWBSB770WJN2) SW4008 SW4007 R4005 R4006 SW4002 SW4003 R4011 R4012 SW4004 SW4006 D4008 D4009 S4701 P4001 B D4010 C OPERATION Unit (Chip Parts Side-A) (QPWBSB770WJN2) A 1 2 3 4 60 5 6
LC-20B4M H G F E D C B A TUNER Unit (Side-A) 1 2 3 4 61 5 6
LC-20B4M TP3701 P3603 P3604 H R3518 J3701 R3519 P3502 Q3601 P3 FH3703 FH3702 FH3701 R3750 FH3704 R3754 Q3709 C3732 R3749 R3745 R374 R3746 IC3702 C3733 R3748 R372 R3734 Q3708 R3521 C3729 R3731 R3752 R3751 R3753 R3719 Q37 R3707 R3755 D3711 C3735 R3737 Q3701 D3701 C3734 G R3738 R3740 C3730 C3731 R R3747 R R3744 Q3707 R C3307 TU3201 F C372 R3732 L37 C3714 L3701 FB37 R3377 C3311 R3322 R3321 R3319 C3313 R3378 C3309 R3331 R3327 Q3306 C3713 C3717 R3362 C3363 C3
LC-20B4M P3301 P3602 P3302 P3601 C3603 D3601 J3409 C3604 R3348 D3605 Q3606 C3328 C3329 R8465 R8466 R8462 R3432 R8460 J3404 R8457 R8454 Q8452 R8455 R8453 R3433 R8452 C8451 R8451 R3430 C3719 R3724 C3724 R3756 C3711 D3709 C8452 Q8451 R3736 FB3708 FB3702 C8453 C3737 L3703 R3729 C3521 R3345 Q3706 R3725 R3342 FB3701 R3722 R3561 C3713 R8458 C8455 C8456 D3707 C3715 T3701 D3705 Q8453 C8454 FB3707 FB3709 C3714 C3723 D3706 C3722 C8458 C8457 R8456 P8401 R8461
LC-20B4M H G F E D C B A INVERTER-A Unit (Side-A) 1 2 3 4 64 5 6
LC-20B4M H FDC4 FH6704 R6708 R6722 Q6708 Q6706 C6712 T6705 R6709 R6711 C6713 R6710 FH6705 Q6707 R6727 R6726 R6725 P6702 C6727 L6704 D6700 G R6705 P6705 Q6704 Q6705 C6714 C6726 R6721 Q6703 FH6702 R6707 C6708 R6706 T6704 C6707 C6709 R6704 L6702 F FH6703 FH6701 FH6700 T6703 E P6701 T6702 C6704 D R6701 C6702 Q6701 R6700 C6703 R6703 R6702 R6720 Q6702 Q6700 C6725 L6700 C P6700 T6701 B FDC1 T6700 A INVERTER-A Unit (Chip Parts Side-A) 1 2 3 4 65 5 6
LC-20B4M H G F E D C INVERTER-B Unit (Side-A) B A 1 2 3 4 66 5 6
LC-20B4M H P6704 G T6709 C6741 F T6708 Q6712 Q6713 C6722 R6716 R6717 L6708 E P6703 C6723 R6718 R6719 FH6708 D T6707 Q6714 R6724 C6740 C6724 Q6710 Q6709 FH6709 R6713 R6723 C6717 L6706 Q6711 D6701 R6712 C6719 R6728 R6729 R6715 C6718 R6714 P6706 C T6706 FH6707 FH6706 INVERTER-B Unit (Chip Parts Side-A) B A 1 2 3 4 67 5 6
LC-20B4M Ref. No. ★ Part No. Description Code Ref. No. Description PARTS LIST DUNTKB750FE06 PARTS REPLACEMENT MAIN UNIT "HOW TO ORDER REPLACEMENT PARTS" To have your order filled promptly and correctly, please furnish the following informations. 1. MODEL NUMBER 2. REF. NO. 3. PART NO. 4. DESCRIPTION ★ MARK: SPARE PARTS-DELIVERY SECTION ★ Part No.
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LC-20B4M CABINET AND MECHANICAL PARTS 25 H 22 4-1 4 11 4-3 4-2 4-6 4-4 4-5 OPERATION PWB D 1-4 25 G INVERTER-A PWB 1-7 1-14 1-10 1-6 24 1-9 MAIN PWB 1-4 1-5 1-11 1-8 INVERTER-B PWB 1-10 1-14 1-13 F 1-9 24 17 1-12 19 1-8 1-4 1-5 E 24 15 16 1-7 1-6 1-4 1-13 18 D 25 R/C, LED PWB 8 24 25 1-3 12 1-2 TUNER PWB 20 E 5-2 1 E 9 5-2-1 1-1 5-8 13 5-5 5 5-18 5-3 5-9 5-2-3 5-19 5-10 5-2-2 D 5-1 21 3-3 5-14 5-15 5-4 3 5-5 5-16 5-7 5-17 5-11 C 5-12
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LC-20B4M PACKING OF THE SET ★ Polyethylene Bag (SSAKA0160CEZZ) Operation Manual (TiNS-A742WJZZ) Cable Clamp (2 pcs.) (LHLDWA002WJSA) ★ "AAA" size Battery (2 pcs.
LC-20B4M 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. TQ1563-S Jun. 2003 Printed in Japan Design and Production Information Design : Japan Production : Japan MI.
