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LG Electronics 42LT640H-ZA Contents of LCD TV Standard Repair Process, Trouble Shooting

Models: 42LT640H-ZA

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1. Trouble Shooting

Contents of LCD TV Standard Repair Process

No.	Error symptom (High category)	Error symptom (Mid category)	Page	Remarks

1		No video/Normal audio	1

2		No video/No audio	2

3	A. Video error	Video error, video lag/stop	3
	A. Video error
4		Color error	4

5		Vertical/Horizontal bar, residual image,	5
5		light spot, external device color error	5
		light spot, external device color error

6		No power	6
	B. Power error
7	B. Power error	Off when on, off while viewing, power auto	7
		Off when on, off while viewing, power auto
		on/off
		on/off

8	C. Audio error	No audio/Normal video	8

9		Wrecked audio/discontinuation/noise	9
9		Wrecked audio/discontinuation/noise	9

10		No response in remote controller, key error,	10
10	D. Function error	recording error, memory error	10
		recording error, memory error

11		External device recognition error	11

12	E. Noise	Circuit noise, mechanical noise	12

13	F. Exterior error	Exterior defect	13

Copyright © 2012 LG Electronics. Inc. All rights reserved.	LGE Internal Use Only
Only for training and service purposes

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Contents

http//eic.lgservice.com READ THE SAFETY PRECAUTIONS IN THIS MANUALhttp//aic.lgservice.com http//biz.lgservice.comSERVICING PRECAUTIONS CONTENTSSAFETY PRECAUTIONS SPECIFICATIONSAFETY PRECAUTIONS IMPORTANT SAFETY NOTICESERVICING PRECAUTIONS Electrostatically Sensitive ES DevicesSmall-Signal Discrete Transistor Removal/Replacement IC Remove/ReplacementReplacement Removal1. Application range SPECIFICATION4. Model General Specification 3. Test methodRemarks SpecificationOnly for training and service purposes RGB Input5.2. RGB Input PC 5. Video resolutions 2D5.1. Component Input Y, CB/PB, CR/PR 5.3. HDMI InputPC/DTV PCDVIAfter downloading, have to adjust Tool Option again ADJUSTMENT INSTRUCTIONBoot file Download 1. Application Range3.1. ADC Process 4. Total Assembly line process4.1. Adjustment Preparation 3.2. Function Check4.3 DDC EDID Write HDMI 256Byte 4.4. EDID data4.2. DDC EDID Write RGB 128Byte Manual W/B process using adjust Remote control4.6.1. HI-POT auto-check preparation 4.5. Outgoing condition Configuration4.6. HI-POT Test 4.6.2. HI-POT auto-check5.2. Comand Set 5.1. Signal Table5. Model name & Serial number D/L 5.3. Method & noticeCI+ Key Value 6.1. Download Procedure6. CI+ Key Download method Copyright BLOCK DIAGRAMS7LR All rights reservedEXPLODED VIEW GP4MSTAR Only for training and service purposesEMEA INTERACTIVE 2011 . 08OLED LGE Internal Use Only Only for training and service purposesCopyright 2012 LG Electronics. Inc. All rights reserved Step Up regulator 3 . 3V to 5VMAX 250mA+1.5VDDR FROM LIPS & POWER B/DPowerDET +3.3VNormalIC501 NTP-7500LCopyright 2012 LG Electronics. Inc. All rights reserved CONTROL IR & LEDOnly for training and service purposes LGE Internal Use Only30Pin LVDS Connector For HD 60HzNormal Only for training and service purposes51Pin LVDS Connector Copyright 2012 LG Electronics. Inc. All rights reservedFor CEC Only for training and service purposesHDMI1 HDMI2LGE Internal Use Only Only for training and service purposesCopyright 2012 LG Electronics. Inc. All rights reserved 0 . 3 3 u FOnly for training and service purposes RGB/SPDIF/PC/HP/USBUSBDIODES Copyright 2012 LG Electronics. Inc. All rights reservedEMEA INTERACTIVE Only for training and service purposesS7LRDIVXMS10 Copyright 2012 LG Electronics. Inc. All rights reservedLGE Internal Use Only Only for training and service purposesCopyright 2012 LG Electronics. Inc. All rights reserved IC1300SI2176ATSC1INPUTH Only for training and service purposesP4RGLOBALTUNERBLOCK SI2156DVB1INPUTHOnly for training and service purposes IC1501LGDT1001 PILG1001 A2Copyright 2012 LG Electronics. Inc. All rights reserved Full Scart/ Comp1Only for training and service purposes LGE Internal Use OnlyEXTSPKCONTROL/DEBUG UART/I2C SWITCHEXTSPK AMP EXTSPK OUTCopyright 2012 LG Electronics. Inc. All rights reserved EXTERNALPOWER OUT 5V/12VOnly for training and service purposes LGE Internal Use OnlyOnly for training and service purposes CI RegionOption name of this page CI SLOT because of Hong Kong Copyright 2012 LG Electronics. Inc. All rights reservedCopyright 2012 LG Electronics. Inc. All rights reserved SMD GASKETOnly for training and service purposes LGE Internal Use OnlyPage Contents of LCD TV Standard Repair Process 1. Trouble ShootingLCD TV A. Video errorMain B/D↔ Power B/D, LVDS Cable,Speaker Cable,IR B/D Cable A2 Check Power Board 24V,12V,3.5V outputOnly for training and service purposes A. Video errorvoltages of Power LCD TVBy using Diagnostics menu on OSD Menu→Setup→Manual Tuning A. Picture ProblemBy using Digital signal level meter Signal strength Normal over 30% Signal Quality Normal over 30%Check color by input -External Input COMPONENT -RGB A. Video errorLCD TV ※ CheckA. Video error Connect other external device and cableExternal device screen error-Color error Vertical/Horizontal bar, residual image, light spotCheck Power LED B. Power errorStand-By Red Operating white Check Power On ‘”High”If Power Off mode is not displayed Check Power B/D voltage B. Power errorCheck Power Off Starusinstart menu POWEROFFABNORMAL1LCD TV C. Audio errorPower Board Check user menu Speaker offLCD TV C. Audio errorIn case of External Input signal error Check and fix external device Check audio B+ Voltage 20V orCheck & Repair Cable connection Connector solder D. General Function Problem1. Remote controlR/C operating error Output signalY Check technical Signal information input? - Fix information D. Function errorCheck input signal S/W VersionLCD TV E. NoiseIdentify nose type F. Exterior defect LCD TVWhen the signal is strong, use the attenuator -10dB, -15dB, -20dB etc A. Video errorVideo error, video lag/stopMENU -Æ red keycustomer support -Æ signal test -Æ select channel Standard Repair Process Detail Technical ManualALL MODELS 1. Checking method for remote controller for adjustmentPress the IN-START with the remote controller for adjustment VersionOnly for training and service purposes A. Video errorColor errorYou can view 6 types of patterns using the ADJ Key Standard Repair Process Detail Technical ManualAppendix Exchange T-Con Board Appendix Exchange T-Con Board Dim Light Appendix Exchange PSULED driverNo Light No picture/Sound Ok A - 3/5Panel Mura, Light leakage Appendix Exchange the ModuleUn-repairable Cases In this case please exchange the module Press damageAppendix Exchange the Module Un-repairable Cases In this case please exchange the moduleB. Power error Off when on, off whiling viewing 1. Press the IN-START button of the remote controller for adjustment2. Check the entry into adjustment item Entry methodChecking method C. Audio errorNo audio/Normal video1. Press the MENU button on the remote controller 2. Select the AUDIO function of the Menu