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JVC LT-37X688 Service Manual
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JVC LT-37X688 Service Manual

Lcd flat television
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SERVICE MANUAL
7 S ERVICE MANUAL
2007
YA535
COPYRIGHT © 2007 Victor Company of Japan, Limited
1
PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
2
SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
3
DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
4
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-18
5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31
LCD FLAT TELEVISION
LT-37X688
LT-42X688
Illustration of LT-37X688

TABLE OF CONTENTS

COPYRIGHT © 2007 Victor Company of Japan, Limited
,
/V
/C
BASIC CHASSIS
FN2
No.YA535
2007/7

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Summary of Contents for JVC LT-37X688

  • Page 1: Table Of Contents

    LT-37X688 LT-42X688 BASIC CHASSIS Illustration of LT-37X688 COPYRIGHT © 2007 Victor Company of Japan, Limited TABLE OF CONTENTS PRECAUTION............... . . 1-3 SPECIFIC SERVICE INSTRUCTIONS .
  • Page 2 SPECIFICATION Contents Items LT-37X688 LT-42X688 Dimensions ( W × H × D ) 91.9 cm × 65.2 cm × 23 cm 103.0 cm × 72.0 cm × 29.6 cm (36-1/4” x 25-3/4” x 9-1/8”) [Included stand] (40-5/8” x 28-3/8” x 11-3/4”) [Included stand] 91.9 cm ×...

  • Page 3: Precaution

    SECTION 1 PRECAUTION SAFETY PRECAUTIONS (1) The design of this product contains special hardware, (6) Isolation Check (Safety for Electrical Shock Hazard) many circuits and components specially for safety After re-assembling the product, always perform an purposes. For continued protection, no changes should be isolation check on the exposed metal parts of the cabinet made to the original design unless authorized in writing by (antenna terminals, video/audio input and output terminals,...

  • Page 4: Digital

    INSTALLATION 1.2.1 HEAT DISSIPATION 1.2.3 INSTALLATION REQUIREMENTS If the heat dissipation vent behind this unit is blocked, cooling To ensure safety in an emergency such as an earthquake, and efficiency may deteriorate and temperature inside the unit will to prevent accidents, ensure that measures are taken to prevent rise.
  • Page 5 HANDLING LCD PANEL 1.3.1 PRECAUTIONS FOR TRANSPORTATION 1.3.2 OPTICAL FILTER (ON THE FRONT OF THE LCD PANEL) When transporting the unit, pressure exerted on the internal LCD (1) Avoid placing the unit under direct sunlight over a panel due to improper handling (such as tossing and dropping) prolonged period of time.
  • Page 6 TUNER DIAGNOSTIC SCREEN This model has a function to check the connection status of the digital tuner. The connection status can be checked following the below procedure. (1) Receive digital broadcasting. (2) Press the [MENU] key to display the user menu. (3) Select "TUNER SETUP"...

  • Page 7: Specific Service Instructions

    SECTION 2 SPECIFIC SERVICE INSTRUCTIONS SYSTEM SETTEING FEATURES Built in ATSC (Advanced Television Systems Committee) Be sure to carry out the following operation at the end of TUNER the procedure. This TV can receive both Digital broadcasting (ATSC) and Analog broadcasting. (1) Set to "0 minutes"...
  • Page 8 SPECIFICATIONS The following table shows the specifications of this unit. Specifications Item LT-37X688 LT-42X688 Maximum dimensions ( W × H × D ) 87.7 cm × 51.5 cm × 5.4 cm 98.3 cm × 57.6 cm × 5.2 cm Weight 11.0 kg...
  • Page 9 2.3.2 MAIN CPU PIN FUNCTION [IC7001 : DIGITAL PWB ASS'Y] Pin name Function Pin name Function VHOLD1 Not used: Data slice for main screen closed caption Not used HFLT1 I/O Not used: LPF for main screen closed caption video input Not used Not used Not used...

  • Page 10: Disassembly

    When removing each board, remove the connector if necessary. The operation is easier if you write down the connection points (connector numbers) of the connector. For connection of each board, refer to the "WIRING DIAGRAM" of the Standard Circuit Diagram. DISASSEMBLY PROCEDURE [LT-37X688/V] 3.2.1 REMOVING THE REAR COVER (Fig.3-1) 3.2.6 REMOVING THE SW PWB (Fig.3-1) (1) Remove the 1 screw [A].
  • Page 11 CORD CLAMP REAR COVER STAND BASE COVER SHIELD COVER MAIN POWER PWB DIGITAL BASE DIGITAL PWB ANALOG PWB SHIELD BASE STAND ASS'Y POWER CORD STAND BASE SUPPORT POWER CORD MAIN BASE HOLDER LED PWB LCD PANEL UNIT SUPPORT BRACKET FRONT PANEL SUPPORT BRACKET SPEAKER CONTROL SW PWB...
  • Page 12 DISASSEMBLY PROCEDURE [LT-42X688/C] 3.3.1 REMOVING THE REAR COVER (Fig.3-2) 3.3.6 REMOVING THE SW PWB (Fig.3-2) (1) Remove the 1 screw [A]. • Remove the REAR COVER. (2) Remove the CORD CLAMP. (1) Remove the 2 screws [M]. (3) Remove the 12 screws [B], the 3 screws [C], and the 5 (2) Remove the SW PWB.
  • Page 13 CORD CLAMP POWER PWB STAND BASE COVER REAR COVER SHIELD COVER ANALOG PWB DIGITAL PWB SHIELD BASE STAND ASS'Y SHIELD BASE POWER CORD HOLDER POWER CORD MAIN BASE STAND BASE SUPPORT LCD PANEL UNIT FRONT PANEL LED PWB SPEAKER SW PWB SPEAKER CONTROL KNOB Fig.3-2...
  • Page 14 MEMORY IC REPLACEMENT • This model uses the memory IC. • This memory IC stores data for proper operation of the video and drive circuits. • When replacing, be sure to use an IC containing this (initial value) data. 3.4.1 MEMORY IC TABLE Symbol Number of pins Mounting PWB Main content of data...
  • Page 15 3.4.4 SETTINGS OF FACTORY SHIPMENT 3.4.4.1 BUTTON OPERATION 3.4.4.2 REMOTE CONTROL DIRECT OPERATION Setting item Setting position Setting item Setting position POWER INPUT CHANNEL CABLE-02 CHANNEL CABLE-02 VOLUME VOLUME INPUT MUTING DISPLAY ASPECT NTSC PANORAMA HD / ATSC FULL SLEEP TIMER VIDEO STATUS DYNAMIC STEREO...
  • Page 16 INITIAL SETUP Setting item Setting position Noise Muting Language English Front Panel Lock V-Chip Set Lock Code 0000 Closed Caption Off(CC1/T1) Auto Shut Off Power Indicator HIGH Optical Out Quick start up EXTERNAL INPUT Setting item Setting position HDMI Size Auto Video-1 Audio Auto...
  • Page 17 REPLACEMENT OF CHIP COMPONENT 3.5.1 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. 3.5.2 SOLDERING IRON (1) Use a high insulation soldering iron with a thin pointed end of it.

  • Page 18: Adjustment

    SECTION 4 ADJUSTMENT ADJUSTMENT PREPARATION SERVICE MODE (1) This TV is adjusted by using REMOTE CONTROL UNIT. 4.5.1 BASIC OPERATION OF SERVICE MODE (2) The adjustment using the REMOTE CONTROL UNIT is Operate the SERVICE MODE with the REMOTE CONTROL made on the basis of the initial setting values.
  • Page 19 4.5.2 SERVICE MODE MENU FLOW CHART SERVICE MODE SCREEN SERVICE MENU SERVICE MENU 1. TV-Micro Service 1. TV-Micro Service 2. Digital Service 2. Digital Service 3. Digital Diagnostics 3. Digital Diagnostics 4. Digital Engineering Functions 4. Digital Engineering Functions DO NOT ADJUST Press [1] key Press [3] key Press [2] key...
  • Page 20 4.5.3 DESCRIPTION OF STATUS DISPLAY 4.5.3.1 TV-MICRO SERVICE MODE (3) VIDEO STATUS SETTING ITEM No. SETTING ITEM SETTING VALUE (DATA) : STANDARD : DYNAMIC : THEATER S001 R DRIVE S001 R DRIVE NTSC3 FULL STD LOW NTSC3 FULL STD LOW GAME : GAME (4) WHITE BALANCE...
  • Page 21 4.5.3.2 DIGITAL SERVICE MODE 1. Adjust (6) SETTING ITEM NO. Setting item numbers are displayed. The setting item numbers to be displayed are listed below. SETTING ITEM No. SETTING ITEM NAME SETTING VALUE (DATA) Setting items Settings Item No. A001 IN LEVEL Audio system setting Adjust A001 - A008...
  • Page 22 INITIAL SETTING VALUE OF SERVICE MODE • Perform fine-tuning based on the "initial values" using the remote control when in the Service mode. • The "initial values" serve only as an indication rough standard and therefore the values with which optimal display can be achieved may be different from the default values.
  • Page 23 Item No. Item Variable range Setting value Item No. Item Variable range Setting value M066 1E41 00 - FF M112 1E6F 00 - FF M067 1E42 00 - FF M113 1E70 00 - FF M068 1E43 00 - FF M114 1E71 00 - FF M069...
  • Page 24 Item No. Item Variable range Setting value Item No. Item Variable range Setting value M158 1E9D 00 - FF M204 1ECB 00 - FF M159 1E9E 00 - FF M205 1ECC 00 - FF M160 1E9F 00 - FF M206 1ECD 00 - FF M161...
  • Page 25 4.6.2 DIGITAL SERVICE MODE SETTING VALUE Setting value Item No. Item Variable range COMPONENT ATSC HDMI 480i 480p 1080i 720p A001 IN LEVEL 0 - 15 A002 LOW SEP 0 - 63 A003 HIGH SEP 0 - 63 A004 DAC CNTL 1 0H - FFH A005 DAC CNTL 2...
  • Page 26 Setting value Item No. Item Variable range COMPONENT ATSC HDMI 480i 480p 1080i 720p C036 TEST REG4 0H - FFH C037 OFST_HLD_DUR 0 - 255 C038 OFST_HLD_DUR_CYC_1 0 - 255 C039 OFST_HLD_DUR_CYC_2 0 - 255 C040 OFST_HLD_MODE 0 - 255 C041 SOG FILTER ENABLE 0 - 1...
  • Page 27 Setting value Item No. Item Variable range COMPONENT ATSC HDMI 480i 480p 1080i 720p X107 RED GAIN COMP HD 0 - 200 X108 GREEN GAIN COMP HD 0 - 200 X109 BLUE GAIN COMP HD 0 - 200 X110 RED GAIN DIGITAL 0 - 200 X111 GREEN GAIN DIGITAL...
  • Page 28 Setting value Item No. Item Variable range COMPONENT ATSC HDMI 480i 480p 1080i 720p X203 SERA MODE COMP 00 - 06 SERA TIME1 COMP 0 - 255 SERA TIME2 COMP 0 - 64 SERA F2 CORING COMP 0 - 120 SERA F4 CORING COMP 0 - 120 SERA F2 GAIN COMP...
  • Page 29 Setting value Item No. Item Variable range COMPONENT ATSC HDMI 480i 480p 1080i 720p S031 VY FILT PV 0H - FFH S032 VY FILT GAME 0H - FFH S033 VY FILT ATSC 525i 0H - FFH S034 VY FILT ATSC 525p 0H - FFH S035 VY FILT ATSC 750p...
  • Page 30 ADJUSTMENT PROCEDURE 4.7.1 VIDEO CIRCUIT [TV-MICRO SERVICE MODE] Measuring Item Test point Adjustment part Description instrument WHITE Remote [1.Adjust] (1) Receive a NTSC 75% all white signal. BALANCE control unit S002: R DRIVE (Red drive) (2) Set "VIDEO STATUS" to "STANDARD". (HIGHLIGHT) S003: G DRIVE (Green drive) (3) Set "ASPECT"...

  • Page 31: Troubleshooting

    SECTION 5 TROUBLESHOOTING SELF CHECK FEATURE 5.1.1 OUTLINE This unit comes with the "Self check" feature, which checks the operational state of the circuit and displays/saves it during failure.Diagnosis is performed when power is turned on, and information input to the main microcomputer is monitored at all time. Diagnosis is displayed in 2 ways via screen display and LED flashes.
  • Page 32 5.1.4 HOW TO EXIT THE SELF CHECK MODE 5.1.6 POINTS TO NOTE WHEN USING THE SELF CHECK FEATURE TO SAVE FAILURE HISTORY: In addition to circuit failures (abnormal operation), the following Turn off the power by unplugging the AC power cord plug when cases may also be diagnosed as "Abnormal"...
  • Page 33 5.1.8 METHOD OF DISPLAY WHEN A RASTER IS NOT OUTPUT In the state where a raster is not output by breakdown of the set, an error is displayed by blink of the POWER LED. Type of error POWER LED flash cycle Low bias line short protection LED turnig on and off at 1 second intervals.
  • Page 34 Victor company of Japan, Limited Display category 12, 3-chome, Moriya-cho, Kanagawa-ku, Yokohama-city, Kanagawa-prefecture, 221-8528, Japan (No.YA535) Printed in Japan...

This manual is also suitable for:

Lt-42x688Lt-42x688/cLt-37x688/v