Manuals / LG Electronics / TV and Video / Flat Panel Television

LG Electronics 42LT640H-ZA C. Audio error, Lcd Tv, Check user menu Speaker off, Check audio B+

Models: 42LT640H-ZA

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Standard Repair Process

	Error	C. Audio error	Established
LCD TV	Error	C. Audio error	date
LCD TV	symptom	No audio/ Normal video	Revised date	8/13
		No audio/ Normal video	Revised date	8/13

No audio Screen normal

☞A24

Check user menu > Speaker off

Off

Cancel OFF

☞A25

Check audio B+	Normal	Y
20V or 24V of	Normal
20V or 24V of	voltage
Power Board	voltage
Power Board

Replace Power Board and repair parts

Check		N
Check		Disconnection
Speaker		Disconnection
Speaker
disconnection
		Y
		Y

		Replace Speaker

Replace MAIN Board

End

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

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LG Electronics 42LT640H-ZA C. Audio error, Lcd Tv, Check user menu Speaker off, Check audio B+, Normal, 20V or 24V of

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 Input5.1. Component Input Y, CB/PB, CR/PR 5. Video resolutions 2D5.2. RGB Input PC 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 & notice6. CI+ Key Download method 6.1. Download ProcedureCI+ Key Value 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 VersionIdentify nose type E. NoiseLCD TV 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

C. Audio error

Check user menu > Speaker off

Check audio B+

Normal

20V or 24V of

voltage

Power Board