JVC LT-20A5 Service Manual
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JVC LT-20A5 Service Manual

JVC LT-20A5 Service Manual

Lcd flat television
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SERVICE MANUAL
11
2005
YA350
1
PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2
SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
3
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
4
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19
5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
LCD FLAT TELEVISION
LT-20A5,
LT-20A5

TABLE OF CONTENTS

COPYRIGHT © 2005 Victor Company of Japan, Limited
/S
No.YA350
2005/11

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Summary of Contents for JVC LT-20A5

  • Page 1: Table Of Contents

    LCD FLAT TELEVISION YA350 2005 LT-20A5, LT-20A5 TABLE OF CONTENTS PRECAUTION............... . . 1-3 SPECIFIC SERVICE INSTRUCTIONS .
  • Page 2 SPECIFICATION Item Contents Dimensions (W × H × D) 54.1cm × 41.6cm × 9.2cm (TV only) 54.1cm × 47.7cm × 12.6cm (Included Stand) Mass 9.0kg (TV only) 10.2kg (Included Stand) TV RF System CCIR B/G, I, D/K, L Color System PAL / SECAM / NTSC3.58 / NTSC4.43 Sound System A2 (B/G, D/K), NICAM (B/G, I, D/K), NTSC-M...

  • Page 3: Precaution

    SECTION 1 PRECAUTION SAFETY PRECAUTIONS (1) The design of this product contains special hardware, (8) When service is required, observe the original lead dress. many circuits and components specially for safety Extra precaution should be given to assure correct lead purposes.
  • Page 4 INSTALLATION 1.2.1 HEAT DISSIPATION If the heat dissipation vent behind this unit is blocked, cooling efficiency may deteriorate and temperature inside the unit will rise. Therefore, please make sure pay attention not to block the heat dissipation vent as well as the ventilation outlet behind the unit and ensure that there is room for ventilation around it.

  • Page 5: Specific Service Instructions

    SECTION 2 SPECIFIC SERVICE INSTRUCTIONS ABOUT LIQUID CRYSTAL DISPLAY 2.1.1 STRUCTURE OF LIQUID CRYSTAL PANEL The Liquid Crystal Display used for this unit is of a TFT (Thin Film Transistor) type panel. The structure of this panel is that a TFT array-formed substrate and the stripe pixel matrix type color filter substrate are pressed together with a liquid crystal filled in between these materials.

  • Page 6: Disassembly

    SECTION 3 DISASSEMBLY DISASSEMBLY PROCEDURE CAUTION: 3.1.1 REMOVING THE CABLE COVER (L/R) AND NECK • Prior to disassembly, unplug the power cord and AC COVER (Fig.1) adapter from the AC outlet without fail. (Turn the power (1) Remove the 4 claws [A]. "off".) (2) Remove the CABLE COVER (L), CABLE COVER (R) and •...

  • Page 7: No.ya350)1

    3.1.2 REMOVING THE STAND ASS'Y (Fig.2) 3.1.4 REMOVING THE AV JACK MODULE (Fig.2) • Remove the NECK COVER. • Remove the CABLE COVER (L). (1) Remove the 4 screws [B] and remove the STAND ASS’Y. (1) Loosen the 2 screws [D]. (2) Remove the AV JACK MODULE by pulling carefully.
  • Page 8 3.1.5 REMOVING THE REAR COVER (Fig.3) • Remove the CABLE COVER (L/R) and NECK COVER. • Remove the STAND ASS’Y. • Remove the TUNER MODULE. • Remove the AV JACK MODULE. (1) Remove the 4 screws [E] and remove the REAR COVER. CAUTION: •...
  • Page 9 3.1.6 REMOVING THE MAIN PWB SHIELD (Fig.4, 5) • Remove the REAR COVER. (1) Remove the 1 screw [F] and remove the D-SUB COVER. (Fig.4) (2) Remove the 1 screw [G] and remove the AUDIO COVER. (Fig.4) (3) Remove the 2 screws [H] and remove the MODULE BRACKETS.

  • Page 10: No.ya350)1

    I x2 MAIN PWB SHIEELD I x2 Fig.5 1-10 (No.YA350)
  • Page 11 3.1.7 REMOVING THE MAIN PWB (Fig.6) • Remove the REAR COVER. NOTE: • Remove the MAIN PWB SHIELD. • EIt is advisable to take note of the connecting location (1) Remove the 1 screw [J]. (connector number) of the removed connectors. (2) Disconnect the connectors [P004] / [P006] / [P009] / [P017] from the MAIN PWB.
  • Page 12 3.1.8 REMOVING THE LCD PANEL UNIT (Fig.7, 8) • Remove the REAR COVER. (1) Remove the 5 screws [L]. (Fig.7) • Remove the MAIN PWB SHIELD. (2) Remove the 2 claws [M], 4 claws [N] and 2 claws [O] and •...
  • Page 13 LCD BRACKET P x 2 Fig.8 (No.YA350)1-13...
  • Page 14 3.1.9 REMOVING THE INVERTER PWB (Fig.9) • Remove the REAR COVER. (1) Remove the 2 screws [Q]. • Remove the MAIN PWB SHIELD. (2) Disconnect the connectors from the INVERTER PWB and • Remove the MAIN PWB. remove the INVERTER PWB. •...
  • Page 15 3.1.10 REMOVING THE SPEAKERS (Fig.10) • Remove the REAR COVER. (1) Disconnect the connector [P612] from the FRONT CONTROL PWB. (2) Strip off the sponges and remove the SPEAKERS. NOTE: • It is advisable to take note of the connecting location (connector number) of the removed connectors.
  • Page 16 3.1.11 REMOVING THE FRONT CONTROL PWB (Fig.11) 3.1.12 REMOVING THE IR SENSOR PWB (Fig.11) • Remove the REAR COVER. • Remove the REAR COVER. (1) Disconnect the connector [P611] from the FRONT (1) Remove the 1 screw [T]. CONTROL PWB. (2) Disconnect the connector [P005] from the IR SENSOR (2) Remove the 2 screws [R].
  • Page 17 FIRMWARE VERSION CHECK 3.2.1 PROCEDURE FOR FIRMWARE VERSION CHECK (1) Press the [MUTING] key and the [DISPLAY] key simultaneously, and the FACTORY MODE screen Fig.1 will be displayed. FACTORY MODE SCREEN (2) The FIRMWARE VERSION is displayed in the upperleft on FIRMWARE Ver.
  • Page 18 REPLACEMENT OF CHIP COMPONENT 3.3.1 CAUTIONS (1) Avoid heating for more than 3 seconds. (2) Do not rub the electrodes and the resist parts of the pattern. (3) When removing a chip part, melt the solder adequately. (4) Do not reuse a chip part after removing it. 3.3.2 SOLDERING IRON (1) Use a high insulation soldering iron with a thin pointed end of it.

  • Page 19: Adjustment

    SECTION 4 ADJUSTMENT This service manual does not describe ADJUSTMENT. (No.YA350)1-19...

  • Page 20: Troubleshooting

    SECTION 5 TROUBLESHOOTING Next No picture appear The voltage of Does the LED The voltage of Replace I025 Replace F001 I025 2pin is 3.3V light up L021, L022 is 12V LED light to Next The voltage of amber The voltage of Replace Replace I009 I009 2pin is 3.3V...
  • Page 21 (No.YA350)1-21...
  • Page 22 Victor Company of Japan, Limited AV & MULTIMEDIA COMPANY DISPLAY CATEGORY 12, 3-chome, Moriya-cho, Kanagawa-ku, Yokohama-city, Kanagawa-prefecture, 221-8528, Japan (No.YA350) Printed in Japan...
  • Page 23 PARTS LIST CAUTION The parts identified by the symbol are important for the safety . Whenever replacing these parts, be sure to use specified ones to secure the  safety. The parts not indicated in this Parts List and those which are filled with lines --- in the Parts No. columns will not be supplied. P.W.
  • Page 24 FRONT CONTROL P.W. BOARD ASS'Y DA-5098801032 (PWB-0916-PART B-01) ........3-9 TUNER P.W. BOARD ASS'Y DA-5098801030 (PWB-0916-PART C-01) ............3-9 PACKING ................................... 3-10 PACKING PARTS LIST ............................. 3-10 USING P.W. BOARD & REMOTE CONTROL UNIT P.W.B ASS'Y LT-20A5 LT-20A5/S ← MAIN P.W.B DA-5098801027 (PWB-0915-PART A-01) ←...

  • Page 25: Exploded View Parts List

    EXPLODED VIEW PARTS LIST  Ref.No. Part No. Part Name Description Local DA-E642204400 FRONT COVER DA-E642204302 FRONT COVER MASK DA-E642440500 JVC MARK DA-5642026411 SP SPONGE (x2) DA-E642025603 HIGH DENSITY SPONGE (x2) DA-E642026500 SPEAKER RUBBER (x8) DA-E055125200 SPEAKER SP01, SP02(x2) DA-E640331800...

  • Page 26: Exploded View

    EXPLODED VIEW 3-4(No.YA350)

  • Page 27: Printed Wiring Board Parts List

    PRINTED WIRING BOARD PARTS LIST MAIN P.W. BOARD ASS'Y Ref No. Part No. Part Name Description Local DA-5098801027 (PWB-0915-PART A-01) C046 DA-E216028903 CAPACITOR 470uF 25V M Ref No. Part No. Part Name Description Local C048 DA-E216028903 CAPACITOR 470uF 25V M C054 DA-E218007993 CAPACITOR...
  • Page 28 Ref No. Part No. Part Name Description Local Ref No. Part No. Part Name Description Local C226 DA-E218007893 CAPACITOR 10uF 16V M C382 DA-E240622091 CAPACITOR 22pF DC 50V J C227 DA-E230003391 CAPACITOR 0.1uF 25V Z C383 DA-E240622091 CAPACITOR 22pF DC 50V J C231 DA-E230003391 CAPACITOR...
  • Page 29 Ref No. Part No. Part Name Description Local Ref No. Part No. Part Name Description Local R045 DA-E134647209 RESISTOR 4.7kΩ 1/10W J R283 DA-E134210009 RESISTOR 100Ω 1/10W F R046 DA-E134633009 RESISTOR 33Ω 1/10W J R285 DA-E134622009 RESISTOR 22Ω 1/10W J R051 DA-E134647209 RESISTOR...

  • Page 30: Ir Sensor P.w. Board Ass'yda-5098801028 (Pwb-0915-Part B-01)

    Ref No. Part No. Part Name Description Local Ref No. Part No. Part Name Description Local RP25 DA-E160310108 NET RESISTOR 22Ω J x4 P009 DA-E782510011 CONNECTOR RP27 DA-E160310101 NET RESISTOR 33Ω J x4 P012 DA-E782511016 CONNECTOR RP29 DA-E160310101 NET RESISTOR 33Ω...

  • Page 31: Front Control P.w. Board Ass'yda-5098801032 (Pwb-0916-Part B-01)

    Ref No. Part No. Part Name Description Local R607 DA-E134275099 RESISTOR 75Ω F R612 DA-E134275099 RESISTOR 75Ω F R613 DA-E134275099 RESISTOR 75Ω F R617 DA-E134275099 RESISTOR 75Ω F L601 DA-E062132317 FERRITE BEADS MLB-160808-0030A-N2 L602 DA-E062132317 FERRITE BEADS MLB-160808-0030A-N2 L603 DA-E062132317 FERRITE BEADS MLB-160808-0030A-N2 L604...

  • Page 32: Packing

    PACKING 10 11 PACKING PARTS LIST  Ref.No. Part No. Part Name Description Local DA-I513530356 CARTON BOX LT-20A5 DA-I513530456 CARTON BOX LT-20A5/S DA-I523530156 CUSHION (L) DA-I523530256 CUSHION (R) DA-I533399956 POLY BAG For SET(x2) DA-I533399856 POLY BAG For SET DA-E061370349 AC ADAPTER ...
  • Page 33 SCHEMATIC DIAGRAMS LCD FLAT TELEVISION LT-20A5, LT-20A5 CD-ROM No. SML200511 COPYRIGHT © 2005 Victor Company of Japan, Limited No.YA350 2005/11...
  • Page 34 LT-20A5 LT-20A5 STANDARD CIRCUIT DIAGRAM CONTENTS USING P.W. BOARD ........................2-1 SEMICONDUCTOR SHAPES ......................2-1 BLOCK DIAGRAM ........................... 2-2 CIRCUIT DIAGRAMS........................2-3 MAIN PWB CIRCUIT DIAGRAM ............................2-3 IR SENSOR PWB CIRCUIT DIAGRAM ..........................2-9 AV JACK PWB CIRCUIT DIAGRAM ..........................2-25 FRONT CONTROL PWB CIRCUIT DIAGRAM .......................

  • Page 35: Block Diagram

    BLOCK DIAGRAM P612 P613 P611 P006 P017 P003 P020 P009 P615 P601 P005 2-2(No.YA350)

  • Page 36: Circuit Diagrams

    CIRCUIT DIAGRAMS MAIN PWB CIRCUIT DIAGRAM (1/11) SHEET1 DC12V OPEN OPEN LCD PANEL UNIT SHEET 7,8 SHEET 7 SHEET 7 MAIN PWB ASS'Y (1/11) PWB-0915-02 (No.YA350)2-3 2-4(No.YA350)
  • Page 37 MAIN PWB CIRCUIT DIAGRAM (2/11) SHEET 2 MAIN PWB ASS'Y (2/11) PWB-0915-02 (No.YA350)2-5 2-6(No.YA350)
  • Page 38 MAIN PWB CIRCUIT DIAGRAM (3/11) SHEET 3 AV JACK PWB ASS'Y P601 SHEET 12 SHEET 3 SHEET 3 SHEET 3 SHEET 8 SHEET 8 SHEET 10 SHEET 3 SHEET 3 SHEET 10 SHEET 3 SHEET 8 SHEET 8 SHEET 7 SHEET 3 SHEET 10 SHEET 3...
  • Page 39 MAIN PWB CIRCUIT DIAGRAM (4/11) SHEET 4 MAIN PWB ASS'Y (8/11) P019 SHEET 8 TUNER PWB ASS'Y P615 MAIN PWB ASS'Y (10/11) SHEET 12 P018 SHEET 10 SHEET 4 SHEET 6, 7, 10 FRONT CONTROL PWB ASS'Y P611 SHEET 12 SHEET 7 IR SENSOR PWB ASS'Y IR SENSOR...
  • Page 40 MAIN PWB CIRCUIT DIAGRAM (5/11) SHEET 5 OPEN SHEET 8 SHEET 7 PANEL UNIT SHEET 5 SHEET 8 SHEET 5 SHEET 5 MAIN PWB ASS'Y (5/11) PWB-0915-02 (No.YA350)2-11 2-12(No.YA350)
  • Page 41 MAIN PWB CIRCUIT DIAGRAM (6/11) SHEET 6 OPEN A-D CONVERT SHEET 8 SHEET 8 SHEET 6 SHEET 7 SHEET 7 SHEET 7,8 SHEET 6 SHEET 6,7 SHEET 6 SHEET 6 PC VGA IN SHEET 6 SHEET 6 SHEET 6,7 SHEET 8 SHEET 6 OPEN SHEET 6...
  • Page 42 MAIN PWB CIRCUIT DIAGRAM (7/11) SHEET 7 SHEET 7, 8 SHEET 7, 8 SHEET 7, 8 OPEN SHEET 7 SHEET 7 SHEET 7 SHEET 3 SHEET 8 SHEET 8 SHEET 5 SHEET 7, 8 SHEET 7 SHEET 7 SHEET 8 SHEET 7, 8 SHEET 6 SHEET 7, 8...
  • Page 43 MAIN PWB CIRCUIT DIAGRAM (8/11) SHEET 8 SHEET 7 SHEET 7 SHEET 8 SHEET 8 SHEET 5 SHEET 6 SHEET 8 SHEET 9 SHEET 6, 7 SHEET 8 SHEET 7 SHEET 8 SHEET 6 SHEET 8 SHEET 7 SHEET 7 SHEET 7 SHEET 7 SHEET 9...
  • Page 44 MAIN PWB CIRCUIT DIAGRAM (9/11) SHEET 9 SHEET 8 SHEET 8 SHEET 8 SHEET 8 SHEET 8 SHEET 8 SHEET 9 SHEET 9 SHEET 9 DDR RAM SHEET 8 SHEET 8 MAIN PWB ASS'Y (9/11) PWB-0915-02 (No.YA350)2-19 2-20(No.YA350)
  • Page 45 MAIN PWB CIRCUIT DIAGRAM (10/11) SHEET 10 SHEET 3 MAIN PWB ASS'Y(4/11) P002 SHEET 4 AUDIO CONTROL SHEET 4,6,7 SHEET 11 SHEET 10 PC AUDIO IN SHEET 11 SHEET 10 OPEN MAIN PWB ASS'Y (10/11) PWB-0915-02 (No.YA350)2-21 2-22(No.YA350)
  • Page 46 MAIN PWB CIRCUIT DIAGRAM (11/11) SHEET 11 SHEET 10 SHEET 10 FRONT CONTROL PWB ASS'Y P613 SHEET 12 SHEET 7 MAIN PWB ASS'Y (11/11) PWB-0915-02 (No.YA350)2-23 2-24(No.YA350)
  • Page 47 AV JACK PWB, FRONT CONTROL PWB ,TUNER PWB CIRCUIT DIAGRAM SHEET 12 TUNER PWB ASS'Y U/V FRONT END SHEET 12 SHEET 12 MAIN ASS'Y (3/11) P020 SHEET 3 MAIN PWB ASS'Y(4/11) P003 SHEET 4 SHEET 12 SHEET 12 SHEET 12 VIDEO-1 VIDEO-2 COMPONENT...

  • Page 48: Pattern Diagrams

    PATTERN DIAGRAMS MAIN PWB AND IR SENSOR PWB PATTERN (No.YA350)2-27 2-28(No.YA350)

  • Page 49: Tuner Pwb Pattern

    AV JACK PWB, FRONT CONTROL PWB, TUNER PWB PATTERN FRONT (No.YA350)2-29 2-30(No.YA350)
  • Page 50 Victor Company of Japan, Limited AV & MULTIMEDIA COMPANY DISPLAY CATEGORY 12, 3-chome, Moriya-cho, Kanagawa-ku, Yokohama-city, Kanagawa-prefecture, 221-8528, Japan (No.YA350) Printed in Japan...

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