LG 42LB551T Service Manual

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LED TV

SERVICE MANUAL

CHASSIS : LB43T

MODEL : 42LB551T

CAUTION

BEFORE SERVICING THE CHASSIS,

READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

P/NO : MFL67982520 (1402-REV00)

North/Latin America

Europe/Africa

Asia/Oceania

42LB551T-TC

Internal Use Only

http://aic.lgservice.com

http://eic.lgservice.com

http://biz.lgservice.com

Printed in Korea

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Summary of Contents for LG 42LB551T

Page 1 Internal Use Only North/Latin America http://aic.lgservice.com Europe/Africa http://eic.lgservice.com Asia/Oceania http://biz.lgservice.com LED TV SERVICE MANUAL CHASSIS : LB43T MODEL : 42LB551T 42LB551T-TC CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. P/NO : MFL67982520 (1402-REV00) Printed in Korea...
Page 2 SPECIFICATION ..................6 ADJUSTMENT INSTRUCTION ............... 8 BLOCK DIAGRAM ................. 14 EXPLODED VIEW .................. 15 SCHEMATIC CIRCUIT DIAGRAM .............. - 2 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 3 An other abnormality exists that must be corrected before the receiver is returned to the customer. - 3 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 5 1. Clip each fuse or resistor lead at top of the circuit board hollow stake. 2. Securely crimp the leads of replacement component around notch at stake top. - 5 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 6 Support HDCP HDMI2-DTV/MHL SPDIF out SPDIF out Except 32”HD model USB Input For My Media(Movie/Photo/Music List) and SVC Headphone - 6 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 7 FHD only(Support to HDMI-PC) 1360*768 @60Hz 47.712 60.015 85.5 VESA(WXGA) WUXGA 1920*1080 @60Hz 67.5 60.0 148.5 FHD only(Support to HDMI-PC) (Reduced blanking) - 7 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 8 If "Error" is displayed, check connection between computer, jig, and set. (3) Click "Read" tab, and then load download file(XXXX.bin) by clicking "Read" filexxx.bin - 8 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 9 * Display and Sound check is executed by Remote control. <Caution> Not to push the "INSTOP" key after completion if the function inspection. - 9 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 10 C0.(When R/G/B Gain are all C0, it is the FULL Dynamic Range of Module) Cool Medium Warm spec target - 10 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 11 Reset 10. 10 Point WB 11. Test Pattern 12. EDID D/L ► 13. Sub B/C 14. Ext. Input Adjust - 11 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 12 Cf) model name in EDID data is below. MODEL NAME MODEL NAME(HEX) LG TV 00 00 00 FC 00 4C 47 20 54 56 0A 20 20 20 20 20 20 20 (LG TV) e. Checksum: Changeable by total EDID data. FHD-8BIT EDID C/S data...
Page 13 (2) When 3D OSD appear automatically, then select OK button. (3) Don't wear a 3D Glasses, check the picture like below. - 13 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 15 X-RADIATION, Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer. - 15 - Copyright © LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 16 2013.05.09 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. TP_NON_EN Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 17 2013.10.28 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR Power_PD2 THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 18 13/04/30 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR USB_S1 THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 19 FIRE AND ELECTRICAL SHOCK HAZARDS, WHEN SERVICING IF IS ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR HDMI_R1_S1 THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 20 2013/10/29 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR SPDIF THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 21 L14_S7LR(M1A) ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR LVDS_NON_EU THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 22 2013/05/20 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR 1_DDR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 23 2013/04/29 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR S_FLASH THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 24 2013/06/05 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR TUNER_KR_AJ THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 25 2013.08.15 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. REAR_JACK_NON_EU Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 26 2013.04.29 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR HEAD_PHONE_EU THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 27 2013/04/30 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR RS232C_MSTAR_DEBUG_4P THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 28 2013/09/03 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR IR_EYE_SENSOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 29 2013/09/16 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MAIN1_NON_EU Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 30 2013.08.15 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. MAIN2_NON_EU Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 31 FIRE AND ELECTRICAL SHOCK HAZARDS, WHEN SERVICING IF IS ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR AUDIO[TI] THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 32 2013.09.01 ESSENTIAL THAT ONLY MANUFACTURES SPECIFIED PARTS BE USED FOR MHL_SW_AND THE CRITICAL COMPONENTS IN THE SYMBOL MARK OF THE SCHEMETIC. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 35 F. Exterior error Exterior defect * First of all, Check whether there is SVC Bulletin in GCSC System for these model. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 36 A-3/5 Other : PSU Inverter/ Module Exchange Module itself (1) A-4/5 Exchange Module itself (2) A-5/5 Continue to the next page Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 37 Always check & record S/W Version and White Replace Main Board Re-enter White Balance value Balance value before replacing the Main Board Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 38 No Video/ Normal voltages of Power replace No audio Voltage Board ( 3.5V,12V, 24V) MAIN B/D Replace Power Board and repair parts Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 39 2. Install Booster Normal Replace Contact with signal distributor S/W Upgrade Picture or broadcaster (Cable or Air) Main B/D Normal Picture Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 40 Contact with signal Change satellite setting S/W Upgrade distributor (match with installed ANT) or broadcaster (Cable or Air) Normal Normal Picture Picture Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 41 Normal Request repair for external device/cable External Check external HDMI device/ device and Replace Main B/D Cable error cable Normal Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 42 (Check normal operation of External Input, HDMI Screen Replace error Component, HDMI by normal Main B/D connecting Jig, pattern Generator ,Set-top Box etc. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 43 Measure voltage of each output of Power B/D Normal ☞A12 ※ Normal Normal Check ST-BY 3.5V Replace Main B/D Voltage Voltage Replace Power B/D Replace Power B/D Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 44 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 © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 45 Speaker off Board Cancel OFF Replace Power Board and repair parts Check Disconn Speaker Replace MAIN Board ection disconnection Replace Speaker Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 46 Request repair to external Audio cable/ANT provider (In case of External Input Check and fix external device signal error) Check and fix external device Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 47 (Power B/D don’t have problem) If R/C operate, Normal Explain the customer Operating cause is interference from light in room. Replace R/C Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 48 - S/W Version Fix in Check and fix HDMI, Optical accordance Replace Main B/D external device/cable with technical Recognition error information Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 49 “Part related to nose” in the Owner’s Manual. as shown in the solution manual (For models without any fix information, provide the description) Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 50 Zoom part with Module Replace module exterior damage damage Cabinet Replace cabinet damage Remote Controller Replace remote controller damage Stand Replace stand damage Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 51 Voltage and speaker checking method in audio/discontinuation case of audio error D. Function error_ No response in Remote controller operation checking method remote controller, key error Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 52 Check Back Light On with naked eye date <ALL MODELS> Power On -> disjoint back case -> check lighting at 2 points. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 53 1. Measure DC 24V applying to inverter PCB from Power Board. 2. Output 24V from Power Board -> supply to inverter PCB. Check Pin contacting statement and connection statement. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 54 3. After recording the R, G, B (GAIN, Cut) value of Color Temp (Cool/Medium/Warm), re- enter the value after replacing the MAIN BOARD. enter the value after replacing the MAIN BOARD. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 55 Check DC 3.5V, 12V, 24V 18 Pin (Power Board ↔ Main Board) SMAW200-H18S5 Power on DRV ON 3.5V PDIM#1 3.5V 3.5V PDIM#2 Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 56 MENU => Press red key Remote controller=>signal test => Select channel When the signal is strong, use the attenuator (-10dB, -15dB, -20dB etc.) Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 57 LCD-TV Version checking method Content date 1. Checking method for remote controller for adjustment Version Press the IN-START with the remote controller for adjustment Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 58 <ALL MODELS> The picture depends on model. As the part connecting to the external input, check the screen condition by signal Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 59 Check and replace Link Cable(LVDS) and contact condition date <ALL MODELS> 1. Check and replace LVDS Cable 2. Check LVDS connection condition Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 60 Checking item : 1. Defective pixel 2. Residual image 3. MODULE error (ADD-BAR,SCAN BAR..) 4.Video error (Classification of MODULE or Main-B/D!) Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 61 Solder defect, CNT Broken Solder defect, CNT Broken T-Con Defect, CNT Broken Abnormal Power Section Solder defect, Short/Crack Solder defect, Short/Crack Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 62 Abnormal Power Section Abnormal Power Section Solder defect, Short/Crack Abnormal Display Fuse Open, Abnormal power section Solder defect, Short/Crack Noise GRADATION GRADATION Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 63 Appendix : Exchange PSU(LED driver) No Light Dim Light Dim Light Dim Light No picture/Sound Ok Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 64 Panel Mura, Light leakage Press damage Crosstalk Press damage Crosstalk Un-repairable Cases In this case please exchange the module. Press damage Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 65 Gate TAB IC Defect Un-repairable Cases In this case please exchange the module. Horizontal Block Gate TAB IC Defect Gate TAB IC Defect Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 66 Content Check front display LED date ST-BY condition: Red Front LED control : Menu  Option  Standby Light  On/Off Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 67 Check DC 3.5V, 12V, 24V 18 Pin (Power Board ↔ Main Board) SMAW200-H18S5 Power on DRV ON 3.5V PDIM#1 3.5V 3.5V PDIM#2 Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 68 Check “power on(Pin 1)” pin is high(about 3.3V) 18 Pin (Power Board ↔ Main Board) SMAW200-H18S5 Power on DRV ON 3.5V PDIM#1 3.5V 3.5V PDIM#2 Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 69 Checking order 1. Press the IN-START button of the remote controller for adjustment 2. Check the entry into adjustment item 3. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 70 1. Press the MENU button on the remote controller 2. Select the AUDIO function of the Menu 3. Select TV Speaker Check Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only Only for training and service purposes...
Page 71 3. Connect the tester RX1 to the speaker terminal and if you hear the Chik Chik sound when you touch the GND and output terminal, the speaker is normal. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only...
Page 72 When checking the Pre-Amp when the power is in ON condition, it is normal when the Analog Tester needle moves slowly, and defective when it does not move at all. Copyright © 2014 LG Electronics. Inc. All rights reserved. LGE Internal Use Only...

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