LG 55LJ55 Series Service Manual Download

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P/NO : MFL69963004 (1703-REV00)

CHASSIS : LA75M

MODEL : 55LJ55**

55LJ55**-U*

LED TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CONFIDENTIAL

Any reproduction, duplication, distribution (including by way of email, facsimile or other electronic means),

publication, modification, copying or transmission of this Service Manual is STRICTLY PROHIBITED unless you

have obtained the prior written consent of the LG Electronics entity from which you received this Service Manual.

The material covered by this prohibition includes, without limitation, any text, graphics or logos in this Service

Manual.

Only training and service purposes

Summary of Contents for 55LJ55 Series

Page 1: ...le or other electronic means publication modification copying or transmission of this Service Manual is STRICTLY PROHIBITED unless you have obtained the prior written consent of the LG Electronics entity from which you received this Service Manual The material covered by this prohibition includes without limitation any text graphics or logos in this Service Manual Copyright 2017 LG Electronics Inc...

Page 2: ... 2 CONTENTS CONTENTS 2 SAFETY PRECAUTIONS 3 SERVICING PRECAUTIONS 4 SPECIFICATION 6 SOFTWARE UPDATE 8 BLOCK DIAGRAM 9 EXPLODED VIEW 10 DISASSEMBLY GUIDE 11 TROUBLE SHOOTING GUIDE APPENDIX ...

Page 3: ...electrical shock Leakage Current Cold Check Antenna Cold Check With the instrument AC plug removed from AC source connect an electrical jumper across the two AC plug prongs Place the AC switch in the on position connect one lead of ohm meter to the AC plug prongs tied together and touch other ohm meter lead in turn to each exposed metallic parts such as antenna terminals phone jacks etc If the exp...

Page 4: ...rth ground Alter natively obtain and wear a commercially available discharging wrist strap device which should be removed to prevent poten tial shock reasons prior to applying power to the unit under test 2 After removing an electrical assembly equipped with ES devices place the assembly on a conductive surface such as aluminum foil to prevent electrostatic charge buildup or expo sure of the assem...

Page 5: ...not shiny reheat them and if necessary apply additional solder Fuse and Conventional Resistor Removal Replacement 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 3 Solder the connections CAUTION Maintain original spacing between the replaced component and adjacent components and the circuit boa...

Page 6: ... each drawing and specification by part number in accordance with BOM 5 The receiver must be operated for about 5 minutes prior to the adjustment 3 Test method 1 Performance LGE TV test method followed 2 Demanded other specification Safety CE IEC specification EMC CE IEC 4 General Specification No Item Specification Remark 1 Market North America 2 Receiving system ATSC NTSC M 64 256 QAM 3 Availabl...

Page 7: ...5 17 VESA VGA O 4 800 600 60Hz 37 87 60 31 40 00 VESA SVGA O 5 1024 768 60Hz 48 36 60 00 65 00 VESA XGA O 6 1152 864 60Hz 54 34 60 05 80 002 VESA O 7 1280 1024 60Hz 63 98 60 02 108 0 VESA SXGA O FHD only 8 1360 768 60Hz 47 71 60 01 85 50 VESA WXGA O 9 1920 1080 60Hz 67 5 60 00 148 5 WUXGA CEA 861D O FHD only No Resolution H freq kHz V freq kHz Pixel clock MHz Proposed DTV 1 640 480 31 46 59 94 25 ...

Page 8: ...ing 6 After finished the update below Pop up appear 7 Click Yes TV will be DC OFF ON 8 After TV turned on Check the updated SW Version and Tool Option 2 NSU This Function is needed to connect to the internet 1 Menu All Settings General About This TV 2 Click CHEK FOR UPDATES system check newest version 3 Click DOWNLOAD AND INSTALL 4 TV is updating 5 After finished the update below Pop up appear 6 T...

Page 9: ...HDMI MUX LVDS USB SPDIF OUT ETHERNET USB1 USB2 OCP 1 5A OCP 1 5A HDMI1 HDMI2 ARC REAR OPTIC LAN 51P FHD DDR3 2133 4Gb x16 X_TAL 24MHz WIFI Only SUB ASSY USB_WIFI DDR3 2133 4Gb x16 HDMI3 SIDE CVBS YPbPr AV COMP REAR EEPROM 256Kb eMMC 5 0 4GB I2S I2C I2C I2C Analog Demod 1866 CVBS SIF X_TAL 32 768kHz 30P HD ...

Page 10: ...n the EXPLODED VIEW It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent Shock Fire or other Hazards Do not modify the original design without permission of manufacturer IMPORTANT SAFETY NOTICE 200 400 800 540 521 120 820 LV1 530 901 902 121 AR1 700 A10 350 200A 200T ...

Page 11: ... 11 DISASSEMBLY GUIDE 2 2 2 2 Fig 1 Fig 2 3 1 3 2 2 2 3 3 3 3 3 4 5 ...

Page 12: ... 12 Fig 3 Fig 4 B B A 6 B B A 6 6 6 6 6 6 6 7 7 8 8 8 8 8 8 8 8 8 8 8 8 8 8 ...

Page 13: ... 13 10 12 11 13 14 14 15 Fig 5 Fig 6 ...

Page 14: ... 14 16 17 18 19 20 20 Fig 7 Fig 8 ...

Page 16: ...uto on off 7 8 C Audio error No audio Normal video 8 9 Wrecked audio discontinuation noise 9 10 D Function error Remote control Local switch checking 10 MR15 operating checking 11 11 12 Wifi operating checking 12 13 Camera operating checking 13 14 External device recognition error 14 15 E Noise Circuit noise mechanical noise 15 16 F Exterior error Exterior defect 16 First of all Check whether ther...

Page 17: ...ays check record S W Version and White Balance value before replacing the Main Board Replace Main Board Re enter White Balance value Precaution Established date Standard Repair Process Revised date 1 16 Error symptom A Video error No video Normal audio A18 A1 A18 A4 A2 First of all Check whether all of cables between board is inserted properly or not Main B D Power B D LVDS Cable Speaker Cable IR ...

Page 18: ...replace MAIN B D Y Replace Power Board and repair parts N End Standard Repair Process A Video error No video No audio A18 Established date Revised date 2 16 Error symptom 2 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 19: ...soldering Normal Picture Y N Y Close Y Close By using Digital signal level meter By using Diagnostics menu on OSD Setting Channels Channel Tuning Manual Tuning Check the Signal Signal strength Normal over 50 Signal Quality Normal over 50 Normal Picture Y Contact with signal distributor or broadcaster Cable or Air N Normal Picture Y Close N A4 Standard Repair Process Established date Revised date 3...

Page 20: ...al device and cable Y External device Cable normal HDMI error Check external device and cable Replace Main T con B D Replace Main T con B D N N A Video error Color error A6 N Y End Replace module Request repair for external device cable Color error Check Test pattern A8 A7 Standard Repair Process Established date Revised date 4 16 Error symptom 4 Copyright 2017 LG Electronics Inc All rights reserv...

Page 21: ...ecting Jig pattern Generator Set top Box etc N Y Replace Main T con B D Screen normal Check screen condition by input External Input Component HDMI DVI Request repair for external device Component error HDMI DVI Connect other external device and cable Check normal operation of External Input Component RGB and HDMI DVI by connecting Jig pattern Generator Set top Box etc Replace Main T con B D Scree...

Page 22: ...f each output of Power B D N Y Normal voltage Replace Main B D Y OK Replace Main B D N Y Normal Check ST BY 7 8V Replace Power B D N Y Normal voltage Replace Power B D Y A17 A18 A18 A18 Standard Repair Process Established date Revised date 6 16 Error symptom 6 Stand By Red or Turn On Operating Turn Off Close Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purpos...

Page 23: ...wer off by OFF TIMER POWEROFF_SLEEPTIMER Power off by SLEEP TIMER POWEROFF_INSTOP Power off by INSTOP KEY POWEROFF_AUTOOFF Power off by AUTO OFF POWEROFF_ONTIMER Power off by ON TIMER POWEROFF_RS232C Power off by RS232C POWEROFF_RESREC Power off by Reservated Record POWEROFF_RECEND Power off by End of Recording POWEROFF_SWDOWN Power off by S W Download POWEROFF_UNKNOWN Power off by unknown status ...

Page 24: ...d and repair parts Check Speaker disconnection N Y Replace Speaker Replace MAIN Board End C Audio error No audio Normal video A20 A21 A18 Disconnection Established date Revised date 8 16 Error symptom Standard Repair Process 8 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 25: ... Connect and check other external device N Y Normal audio Check and fix external device Replace Power B D N Y Normal voltage Check input signal RF External Input signal Signal normal When RF signal is not received Request repair to external cable ANT provider Y Check audio B Voltage 13V Replace Main B D In case of External Input signal error Check and fix external device Replace Main B D N End Est...

Page 26: ...ce Baterry of R C Check Repair Cable connection Connector solder Normal operating Check B 13V On Main B D A22 Normal Voltage Close N N Check 13v on Power B D Replace Power B D or Replace Main B D Power B D don t have problem A18 Check IR Output signal Normal Signal N Y Repair Replace IR B D N A22 Replace Main B D Y A22 Standard Repair Process Established date Revised date 10 16 Error symptom 10 Y ...

Page 27: ...onnection N Check the Wifi wafer 1pin Standard Repair Process Established date Revised date 12 16 Error symptom 12 Change the Wifi assy Normal Voltage Close Y Y N Replace Main B D Wi Fi Mac value is NG N Close A24 A4 A4 A24 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 28: ... external device cable HDMI DVI Optical Recognition error Replace Main B D Replace Main B D Fix in accordance with technical information D Function error External device recognition error Established date Revised date 14 16 Error symptom Standard Repair Process 14 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 29: ...in the solution manual For models without any fix information provide the description Mechanical noise is a natural phenomenon and apply the 1st level description When the customer does not agree apply the process by stage Describe the basis of the description in Part related to nose in the Owner s Manual E Noise Circuit noise mechanical noise Established date Revised date 15 16 Error symptom Stan...

Page 30: ...eplace remote control Remote control damage Stand dent Replace stand F Exterior defect Exterior defect Established date Revised date 16 16 Error symptom Standard Repair Process 16 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 31: ...A5 7 A Video error _Vertical Horizontal bar residual image light spot Connection diagram A6 8 A Video error_ Color error Check Link Cable EPI reconnection condition A7 9 Adjustment Test pattern ADJ Key A8 10 Appendix Defected Type caused by T Con Inverter Module Exchange Main Board 1 A 1 5 11 Exchange Main Board 2 A 2 5 12 Exchange Power Board PSU A 3 5 13 Exchange Module 1 A 4 5 14 Exchange Modul...

Page 32: ...ing POWER OFF MODE checking method A19 19 C Audio error_ No audio Normal video Checking method in menu when there is no audio A20 20 Voltage and speaker checking method when there is no audio A21 21 D Function error Remote control operation checking method A22 22 Wifi operation checking method A23 Continued from previous page Copyright 2017 LG Electronics Inc All rights reserved Only for training ...

Page 33: ...eck LCD back light with naked eye A Video error_No video Normal audio After turning on the power and disassembling the case check with the naked eye whether you can see light from locations A1 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 34: ...o A2 Entry method 1 Press the ADJ button on the remote control for adjustment 2 Enter into White Balance of item 10 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 ALL MODELS Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 35: ...Standard Repair Process Detail Technical Manual TUNER input signal strength checking method A Video error_Video error video lag stop ALL MODELS A3 Established date Revised date Error symptom Content A3 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 36: ...g stop 1 Checking method for remote control for adjustment Press the IN START with the remote control for adjustment Version ALL MODELS A4 Established date Revised date Error symptom Content A4 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 37: ...ltage from power supply finally replace the MAIN BOARD Standard Repair Process Detail Technical Manual TUNER checking part A Video error_Video error video lag stop ALL MODELS A5 Established date Revised date Error symptom Content A5 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 38: ...ntal bar residual image light spot As the part connecting to the external input check the screen condition by signal A6 Established date Revised date Error symptom Content A6 ALL MODELS Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 39: ...on A Video error_Color error Check the contact condition of the Link Cable especially dust or mis insertion A7 Established date Revised date Error symptom Content A7 ALL MODELS Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 40: ...patterns using the ADJ Key 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 A8 Established date Revised date Error symptom Content A8 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 41: ...Solder defect CNT Broken Solder defect CNT Broken Solder defect CNT Broken Abnormal Power Section Solder defect Short Crack Abnormal Power Section Solder defect Short Crack Appendix Exchange Main Board 1 A 1 5 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 42: ...r Section Solder defect Short Crack Fuse Open Abnormal power section Noise GRADATION GRADATION Abnormal Display Appendix Exchange Main Board 2 A 2 5 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 43: ...ix Exchange Power Board PSU No Light Dim Light Dim Light Dim Light No picture Sound Ok A 3 5 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 44: ... 1 Crosstalk Crosstalk Press damage Press damage Un repairable Cases In this case please exchange the module Press damage Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 45: ...k Source TAB IC Defect Horizontal Block Gate TAB IC Defect Horizontal line Gate TAB IC Defect Gate TAB IC Defect Horizontal Block Gate TAB IC Defect Appendix Exchange the Module 2 A 5 5 Un repairable Cases In this case please exchange the module Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 46: ...er Indicator B Power error _No power A17 Established date Revised date Error symptom Content A17 ST BY condition On or Off Power ON condition Turn Off Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 47: ...and ST BY 3 5V B Power error _No power A18 Check the DC 13 2V Backlight Forward Voltage Symbol Values Unit Min Typ Max 43LJ5500 UA Vf 65 94 72 45 Vdc 49LJ5500 UA Vf 113 4 122 4 Vdc 55LJ5500 UA Vf 125 2 127 2 142 4 Vdc Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 48: ...em 3 Standard Repair Process Detail Technical Manual POWER OFF MODE checking method B Power error _Off when on off whiling viewing ALL MODELS A19 Established date Revised date Error symptom Content A19 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 49: ...elect TV Speaker Standard Repair Process Detail Technical Manual Checking method in menu when there is no audio C Audio error_No audio Normal video ALL MODELS A20 Established date Revised date Error symptom Content A20 Copyright 2017 LG Electronics Inc All rights reserved Only for training and service purposes LGE Internal Use Only ...

Page 50: ...er terminal and if you hear the Chik Chik sound when you touch the GND and output terminal the speaker is normal Standard Repair Process Detail Technical Manual Voltage and speaker checking method when there is no audio C Audio error_No audio Normal video A21 Established date Revised date Error symptom Content A21 1 SPK_R 2 SPK_R 3 SPK_L 4 SPK_L Copyright 2017 LG Electronics Inc All rights reserve...

Page 51: ...ontrol operation checking method D Function error A22 Established date Revised date Error symptom Content A22 Checking order to check remote control IR EYE Sensor IR LOGO light Rear IR Eye P4001 1 3 4V_WIFI 2 WIFI_DM 3 WIFI_DP 4 GND 5 WOL WIFI_POWER_ON 6 3 4V_WIFI 7 NC 8 GND 9 NC 10 NC 11 GND 12 GND 13 NC 14 NC 15 NC 16 I2C_SDA_EYE 17 I2C_SCL_EYE 18 GND 19 IR 20 LED_R 21 GND 22 3 4V_ST 23 KEY2 24 ...

Page 52: ...the 3 5V on the terminal Checking order to check WiFi Wifi Assy Front Wifi Assy Rear WiFi AC only Model P4001 1 3 4V_WIFI 2 WIFI_DM 3 WIFI_DP 4 GND 5 WOL WIFI_POWER_ON 6 3 4V_WIFI 7 NC 8 GND 9 NC 10 NC 11 GND 12 GND 13 NC 14 NC 15 NC 16 I2C_SDA_EYE 17 I2C_SCL_EYE 18 GND 19 IR 20 LED_R 21 GND 22 3 4V_ST 23 KEY2 24 KEY1 25 GND Copyright 2017 LG Electronics Inc All rights reserved Only for training a...

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