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LG 37LH50YD Service Manual

Chassis: lb91b
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LCD TV

SERVICE MANUAL

CHASSIS : LB91B
MODEL : 37LH50YD
CAUTION
37LH50YD-AA

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Summary of Contents for LG 37LH50YD

  • Page 1: Service Manual

    LCD TV SERVICE MANUAL CHASSIS : LB91B MODEL : 37LH50YD 37LH50YD-AA CAUTION...
  • Page 4 SAFETY PRECAUTIONS NOTE: Use with this receiver only the test fixtures specified in this service manual. Electrostatically Sensitive (ES) Devices.
  • Page 5 Removal At IC Connections Replacement At Other Connections...

  • Page 6: Application Range

    760.0 (H) x 450.0 (V) x 48.0 (D) Wihtout inverter Pixel Pitch 0.42675 (H) x 0.42675 (V) Back Light EEFL Display Colors 1.06Billion Coating 3H, Semi-glare Copyright ©2009 LG Electronics. Inc. All right reserved. - 6 - LGE Internal Use Only Only for training and service purposes...
  • Page 10 - For New Zealand, Australia Model 32LH50YD 37LH50YD 42LH50YD 47LH50YD 55LH50YD option Tool Option1 (16833) (20929) (25025) (33217) (45505) Tool Option2 (3144) (3144) (3144) (3144) (3144) Tool Option3 (52132) (52132) (52132) (52132) (52132) Tool Option4 (4352) (4352) (4352) (4352) (4352)

  • Page 14: Exploded View

    X-RADIATION, Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer. Copyright LG Electronics. Inc. All right reserved. - 14 - LGE Internal Use Only Only for training and service purposes...
  • Page 15 2009.01.19 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MAIN_1 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 16 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MAIN_2 MAIN_2 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 17 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. DDR2 DDR2 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 18 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. INTERFACE INTERFACE Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 19 EAX60148002-0(LH50) 2009.01.19 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 20 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. HDMI HDMI Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 21 EAX60148002-0(LH50) 2009.01.19 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 22 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. POWER POWER Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 23 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MST7323S(FRC) MAIN Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 24 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MST7323S DDR2 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 25 ESSENTIAL THAT ONLY MANUFATURES SPECFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. TUNER 11_TUNER Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and servcie purposes LGE Internal Use Only...
  • Page 27 Circuit noise, mechanical noise F. Exterior error Exterior defect First of all, Check whether there is SVC Bulletin in GCSC System for these model. Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 28 Always check & record S/W Version and White Replace Main Board Re-enter White Balance value Balance value before replacing the Main Board Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 29 Power No Video/ replace voltage? No audio Board ( 5V,12V,20V MAIN B/D or 24V…) Replace Power Board and repair parts Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 30 Normal Contact with signal distributor Picture? or broadcaster (Cable or Air) Check Normal Tuner soldering Picture? Close Replace Main B/D Close Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 31 Request repair for external device/cable RGB/ Check external External device device and Replace Main B/D HDMI/DVI /Cable error cable normal Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 32 (Check normal operation of Main B/D normal? External Input, Component, HDMI/ RGB and HDMI/DVI by connecting Jig, pattern Generator ,Set-top Box etc. Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...

  • Page 33: Power Error

    If mechanical power switch off → Doesn’t turn on by remote control → Doesn’t appear LED light Please refer to the A21 Page Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 34 Power off by unknown status except listed case "POWEROFF_ABNORMAL1" Power off by abnormal status except CPU trouble Abnormal "POWEROFF_CPUABNORMAL" Power off by CPU Abnormal Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...

  • Page 35: Audio Error

    Power Board Cancel OFF and describe Replace Power Board and repair parts Check Disconnection Replace MAIN Board Speaker disconnection Replace Speaker Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 36 External Input Connect and check Normal signal error) other external audio? Check and fix device external device Check and fix external device Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 37 Signal? Operation Output signal Connector solder (Key PCB + tool ) Close Close Repair/Replace Move Local switch B/D Power problem Section Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...

  • Page 38: Function Error

    - S/W Version RGB,HDMI/ Check and fix DVI, Optical Replace Main B/D Fix in external device/cable Recognition error accordance with technical information Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 39 ※ Describe the basis of the description (For models without any fix information, in “Part related to nose” in the Owner’s provide the description) Manual. Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 40 Zoom part with Replace module exterior damage damage Cabinet Replace cabinet damage Remote controller Replace remote controller damage Stand Replace stand dent Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 41 AV Audio out / No Audio (Headphone & SPDIF) USB / Remocon Problem USB no connect / Remocon Intelligent Sensor Intelligent Sensor Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 42 Replace MAIN B’D IC102 Replace MAIN B’D IC103 Replace MAIN B’D Replace MAIN B’D IC100 NAND FLASH Serial Flash IC300, IC301 DDR2 Memory Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 43 MAIN B’D L810 = 12V ? Replace MAIN B’D Q805 Check LVDS Cable Replace Main Board OK ? Replace LVDS Cable Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 44 Replace MAIN B’D IC1103 MAIN B’D L1113 = 1.8V ? Replace MAIN B’D IC1105 MAIN B’D X1101 Clock ? Replace MAIN B’D X1101 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 45 Replace MAIN B’D IC1103 MAIN B’D L1113 = 1.8V ? Replace MAIN B’D IC1105 MAIN B’D X1101 Clock ? Replace MAIN B’D X1101 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 46 Replace MAIN B’D JK402 Video Signal ? Check MAIN B’D C217 Replace Video Signal ? MAIN B’D C217 Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 47 Replace MAIN B’D JK404 Video Signal ? Check MAIN B’D C211 Replace Video Signal ? MAIN B’D C211 Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 48 C201 (Pb) Replace C202 (Pr) MAIN B’D C200 or C203 or C201 or C202 Video Signal ? Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 49 C215 (Pb) Replace C216 (Pr) MAIN B’D C214 or C209 or C215 or C216 Video Signal ? Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 50 Check MAIN B’D C207 (Video) Replace R2030 (HSYNC) MAIN B’D C207 or R2030 or R2031 R2031 (VSYNC) Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 51 Check MAIN B’D C2016 (RED) C2017 (GREEN) Replace C2018 (BLUE) MAIN B’D C2016 or C2017 or C2018 Video Signal ? Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 52 Check the ADJUST MENU (Refer to Adjustment Spec) EDID OK ? Replace MAIN B’D IC601 (HDCP KEY) Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 53 MAIN B’D JACK Check JK600 -> HDMI1 JK601 -> HDMI2 JK602 -> HDMI3 JK603 -> HDMI4 Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 54 L705 Pin #1 Check P700 Cable Replace MAIN B’D IC701 L704 Pin #2 PWM Signal ? Replace MAIN B’D IC 701 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 55 2009. 2 . 1 Digital TV No Audio Problem LCD TV Symptom 14/25 Revision Digital TV Video OK ? Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 56 Analog TV Video OK ? Check MAIN B’D Replace MAIN B’D IC100 R2046 Signal (SIF) MAIN B’D Replace MAIN B’D IC1102 L1101 Signal (SIF) Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 57 Replace MAIN B’D JK402 MAIN B’D C2011 (Right Sound) Replace MAIN B’D IC 100 C2012 (Left Sound) signal ? Check MAIN B’D C229, C230 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 58 Replace MAIN B’D JK402 MAIN B’D C2008 (Right Sound) Replace MAIN B’D IC 100 C2009 (Left Sound) signal ? Check MAIN B’D C2008, C2009 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 59 Replace MAIN B’D JK402 MAIN B’D C229 (Right Sound) Replace MAIN B’D IC 100 C230 (Left Sound) signal ? Check MAIN B’D C229, C230 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 60 Replace MAIN B’D JK402 MAIN B’D C2013 (Right Sound) Replace MAIN B’D IC 100 C2014 (Left Sound) signal ? Check MAIN B’D C2013, C2014 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 61 Replace MAIN B’D JK401 MAIN B’D C2015 (Right Sound) Replace MAIN B’D IC 100 C2016 (Left Sound) signal ? Check MAIN B’D C2015, C2016 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 62 Check the ADJUST MENU Download EDID EDID OK ? (Refer to Adjustment Spec) Replace MAIN B’D IC100 Check the HDMI Cable Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 63 Check the SPDIF Cable Check MAIN B’D JK403 Replace MAIN B’D JK403 Check MAIN B’D R2305 PWM Signal ? Replace MAIN B’D IC 100 Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 64 JK406 Pin #1 5V ? Check MAIN B’D Replace MAIN B’D IC808 R826 5V ? Check MAIN B’D Replace POWER B’D R848 12V ? Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 65 24/25 Revision Check MAIN B’D P5001 Replace it Wafer & Connector Check IR B’D P1 Wafer Replace IR B’D & Connector Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...
  • Page 66 25/25 Revision Check MAIN B’D P5001 Replace it Wafer & Connector Check IR B’D P1 Wafer Replace IR B’D & Connector Copyright ⓒ 2009 LG Electronics. Inc. All right reserved. Only for training and service purposes LGE Internal Use Only...

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