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P/NO : MFL71663906 (1908-REV00)

CHASSIS : UA9BW

MODEL : 55UT672M0UC

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.

Copyright © 2019 LG Electronics Inc. All rights reserved. Only training and service purposes.

Summary of Contents for 55UT672M0UC

Page 1: ... 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 2019 LG Electronics Inc A...

Page 2: ...ghts reserved Only for training and service purposes CONTENTS CONTENTS 2 SAFETY PRECAUTIONS 3 SERVICING PRECAUTIONS 4 SPECIFICATION 6 SOFTWARE UPDATE 11 BLOCK DIAGRAM 13 EXPLODED VIEW 14 DISASSEMBLY GUIDE 16 TROUBLE SHOOTING GUIDE APPENDIX ...

Page 3: ...he set is safe to operate without damage of 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 ...

Page 4: ...c charge on your body by touching a known earth 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 electrosta...

Page 5: ...oints of the two original leads If they are 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...

Page 6: ... test method followed 2 Demanded other specification Safety CE IEC specification EMC CE IEC 4 General Specification No Item Specification Remarks 1 Market North America 2 Broadcasting system ATSC NTSC M 64 256 QAM 3 Available Channel VHF 2 13 UHF 14 69 DTV 2 69 CATV 1 135 CADTV 1 135 4 Receiving system Digital ATSC 64 256 QAM Analog NTSC M 5 Video Input NTSC M Rear Refer 5 6 Component Input Y Cb C...

Page 7: ...en Blue Red 5 Audio Input 1 Component Audio DVI Audio RCA White Red 6 Audio Output 1 SPDIF out S PDIF Optical 7 USB 2 EMF DivX HD For SVC download Side 1EA Rear 1EA 1 Side 1EA Rear 0EA 2 Side 2EA Rear 0EA 8 RS 232C IN Control Service 1 D SUB 9PIN Type Phone Jack type 9 Game Control M P I 1 Game Conteol M P I M P I 10 TV LINK CFG 1 11 RJP 1 12 Speaker Out Line Out 1 13 LAN 2 AUX LAN LAN 1 LAN 14 Se...

Page 8: ...duced Blanking 11 1920 1080 135 00 120 00 297 WUXGA Reduced Blanking 12 2560 1440 88 78 59 95 241 5 UHD 60Hz 13 3840 2160 53 95 23 98 297 UDTV 2160P 14 3840 2160 54 00 24 00 297 UDTV 2160P 15 3840 2160 56 25 25 00 297 UDTV 2160P 16 3840 2160 61 43 29 97 297 UDTV 2160P 17 3840 2160 67 50 30 00 297 UDTV 2160P 18 3840 2160 112 50 50 00 594 UDTV 2160P 19 3840 2160 134 86 59 94 594 UDTV 2160P 20 3840 2...

Page 9: ... 30 00 79 2 HDTV 1080p 16 1920 1080 56 25 50 00 148 5 HDTV 1080p 17 1920 1080 67 43 59 94 148 35 HDTV 1080p 18 1920 1080 67 50 60 00 148 5 HDTV 1080p 19 1920 1080 112 50 100 00 297 HDTV 1080p 20 1920 1080 134 86 119 88 296 7 HDTV 1080p 21 1920 1080 135 00 120 00 297 HDTV 1080p 22 3840 2160 53 95 23 98 296 7 UDTV 2160p 23 3840 2160 54 00 24 00 297 UDTV 2160p 24 3840 2160 56 25 25 00 297 UDTV 2160p ...

Page 10: ...680 4320 132 30 1188 8K 8K Model Only 52 7680 4320 220 50 2376 8K 8K Model Only 53 7680 4320 263 74 59 94 2376 8K 8K Model Only 54 7680 4320 264 60 2376 8K 8K Model Only No Resolution H freq kHz V freq kHz Pixel clock MHz Proposed 1 720 480i 15 73 59 94 13 5 SDTV DVD 480I 525I 2 720 480i 15 75 60 13 514 SDTV DVD 480I 525I 3 720 576i 15 625 50 13 5 SDTV DVD 576I 625I 50Hz 4 720 480p 31 47 59 94 27 ...

Page 11: ...button 4 TV is updating 5 After finished the update below Pop up appears then TV will reboot automatically 6 Check the updated SW Version and Tool Option If the software version on the USB device is equal to or lower than the version currently installed on the TV it cannot be updated in User Mode 2 Expert Mode 1 Menu General press 7 consecutively by remote control until TV Manager application is l...

Page 12: ...a Coning make and apply clone file Image Download Image Download downloads Boot Logo Image Apps Background Image s and Hotel Directory Image s at once Icon Download Icon Download downloads Hotel Icon on Portal Website Shortcut and Input Shortcut images at once Video Download Video Download downloads Hotel Video and Welcome Video files at once Software Update download software firmware Micom or CPU...

Page 13: ...MMC 4GB DDR3 2133 X 16 512MB X 2EA SYSTEM EEPROM 256Kb X_TAL 24MHz I2S Out SPDIF OUT BLUTOOTH WIFI SUB ASSY Tuner I2C 5 D Demod I2C 2 IF CVBS SIF USB1 2 0 HDMI2 2 0 ARC OCP 1 5A TI MICOM IR Key Eye UART S W Debug X_TAL 32 768MHz I2C 1 Tx Rx Ti Micom Data Demod RF b LAN Game Control MPI MPI SPI Rear TV LINK CFG Side Side Pillow SPK AMP Trans Pillow SPK Rear Rear HDMI1 2 0 USB2 2 0 Rear Rear ...

Page 14: ...cteristics These parts are identified by in 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 200A 800 HP1 400 540 200P LV1 521 570 530 HS1 HW1 700 571 500 820 LV2 121 120 ...

Page 15: ...nc All rights reserved Only for training and service purposes MRC use only MRC Module Repair Center IMPORTANT NOTICE EXPLODED VIEW MODULE POL Front Panel Ass y POL Rear Optical Sheet Rear Side 200PPF 200PPR 200P 200PC 200SL1 200SR1 ...

Page 16: ...Cover 1 Module Bottom Assembly 2 Screw 2 Assembly 3 Rear AV Screw 3 Assembly Do not wear items that may damage the appearance of the product SCREW TORQUE 5 7Kgf cm Insert your finger in the left right triangle hole indicated by the red circle to disassemble the back cover Back Cover Work Order 1 Back Cover Screw disassemble 2 Insert the finger of the back cover bottom section triangle hole and dis...

Page 17: ...the Main PSU SPK Wifi IR Step 2 Disassemble the S PCB Cover Shield Step 3 Disassemble the Case Top Screw back screw Step 4 LCM reverse and disassemble Source PCB from Holder Step 5 Disassemble the Case Top Screw side screw and Case Top Rear Sliver screw 5ea Screw top 7 EA side L 5ea side R EA Hook top 6ea side L 5 EA side R 5 EA Screw down 7 EA ...

Page 18: ...ses Step 6 6 Disassemble the Panel Step 7 6 Disassemble the guide panel Step 8 Disassemble the Optical Sheet Prism up Prism down DP Step 9 Disassemble the DPS LED Fixer Reflector Sheet Rotate the DPS to remove 9 EA Push LED fixer in back 4 EA Hook top 8 EA side L 4 EA side R 4 EA down 7 EA ...

Page 19: ...Bottom LED Array Assemble Step 1 Attach the Double Tape 1 Attach the Double Tape in Guide Line of Cover Bottom 4ea 2 Remove the protect film of Double Tape Step 2 Attach the LED Array 1 Attach the LED Array to the round hole on Cover Bottom embo 2 Press the LED Array on the surface of Cover Bottom 3 Connect the CNT to the LED Array C Bottom Guide Line Completion of double tape attach 4ea Finish th...

Page 20: ...TROUBLE SHOOTING GUIDE Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 21: ...Main PCB Audio SIZE 270x174 1 Main processor DDR Memory 2 Audio AMP Power from PSU PANEL IR Ass y 1 2 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 22: ...Interconnection 1 2 3 4 5 1 2 3 4 Main PCB PSU PANEL FFC Cable Local Key IR ASSY 5 SPEAKER Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 23: ... 7 Off when on off while viewing power auto 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 11 External device recognition error 11 12 E Noise Circuit noise mechanical noise 12 13 F Exterior error Exterior defect 13 14 G Commercial Feature IR OUT 14 First of all Check whether there is SVC Bulletin ...

Page 24: ...s End Always 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 14 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 ...

Page 25: ...k and 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 14 Error symptom 2 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 26: ...n B D Check Tuner soldering Normal Picture Y N Y Close Y Close By using Digital signal level meter By using Diagnostics menu on OSD Menu 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 Establis...

Page 27: ...Check external 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 14 Error symptom 4 Copyright 2019 LG Electronics Inc All r...

Page 28: ...VI by connecting 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 AV RGB HDMI DVI Request repair for external device Comp AV RGB error HDMI DVI Connect other external device and cable Check normal operation of External Input Comp AV RGB and HDMI DVI by connecting Jig pattern Generator Set top Box etc Replace Mai...

Page 29: ...e voltage of 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 3 5V 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 14 Error symptom 6 Stand By Red or Turn On Operating Turn Off Close Copyright 2019 LG Electronics Inc All rights reserved Only for training and ser...

Page 30: ...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 except listed case Abnormal POWEROFF_ABNO...

Page 31: ... Power Board 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 14 Error symptom Standard Repair Process 8 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 32: ...ernal Input 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 ...

Page 33: ...heck Replace Baterry of R C Check Repair Cable connection Connector solder Normal operating Check B 3 5V On Main B D A22 Normal Voltage Close N N Check 3 5v 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 14 Error s...

Page 34: ...r Check and fix external device cable HDMI DVI 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 11 14 Error symptom Standard Repair Process 11 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 35: ...s shown in the solution manual For models without any fix information provide the description OR 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 12 14 Error s...

Page 36: ...e cabinet Replace remote control Remote control damage Stand dent Replace stand F Exterior defect Exterior defect Established date Revised date 13 14 Error symptom Standard Repair Process 13 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 37: ...ide Established date Revised date 14 14 Error symptom Standard Repair Process Y Change cable N N Suitable Data Format Change Remote Y Replace MAIN Board End Check Remote Controller data Format A24 14 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 38: ...ecking Part A5 6 A Video error _Vertical Horizontal bar residual image light spot Connection diagram A6 7 A Video error_ Color error Check Link Cable EPI reconnection condition A7 8 Adjustment Test pattern ADJ Key A8 9 Appendix Defected Type caused by T Con Inverter Module Exchange Main Board 1 A 1 5 10 Exchange Main Board 2 A 2 5 11 Exchange Power Board PSU A 3 5 12 Exchange Module 1 A 4 5 13 Exc...

Page 39: ...POWER OFF MODE checking method A19 17 C Audio error_ No audio Normal video Checking method in menu when there is no audio A20 18 Voltage and speaker checking method when there is no audio A21 19 D Function error Remote control operation checking method A22 20 G Commercial IR OUT Cable connection Recommended data format A23 Continued from previous page Copyright 2019 LG Electronics Inc All rights r...

Page 40: ...nt Check 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 ALL MODELS Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 41: ...f item 6 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 Entry method 1 Press the ADJ button on the remote controller for adjustment 2 Enter into White Balance of item 13 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 2019 LG ...

Page 42: ...tc 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 43: ...or video lag 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 44: ...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 A5 Established date Revised date Error symptom Content A5 Interface Jack depends on model Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 45: ...ontal 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 Interface Jack depends on model Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 46: ...ion condition 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 47: ...6 types of 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 48: ...CNT Broken 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 49: ...normal Power Section Solder defect Short Crack Fuse Open Abnormal power section Noise GRADATION GRADATION Abnormal Display Appendix Exchange Main Board 2 A 2 5 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 50: ...Appendix Exchange Power Board PSU No Light Dim Light Dim Light Dim Light No picture Sound Ok A 3 5 Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 51: ...odule 1 A 4 5 Crosstalk Crosstalk Press damage Press damage Un repairable Cases In this case please exchange the module Press damage Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 52: ...rtical Block 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 53: ...Technical Manual Check front Power Indicator B Power error _No power A17 Established date Revised date Error symptom Content A17 ALL MODELS Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 54: ... Detail Technical Manual Revised date A18 Error symptom Content Check power input voltage and ST BY 3 5V B Power error _No power A18 Check the DC 13V Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 55: ...justment item 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 56: ...Sound Out 4 Select 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 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 57: ...peaker 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 ALL MODELS 1 SPK_R 2 SPK_R 3 SPK_L 4 SPK_L Copyright 2019 LG Electronics Inc All...

Page 58: ...y otherwise it s defective Standard Repair Process Detail Technical Manual Remote control operation checking method D Function error A22 Established date Revised date Error symptom Content A22 Checking order to check remote control IR LOGO light Rear IR Eye LED IR LOGO light Front IR assy depends on model Copyright 2019 LG Electronics Inc All rights reserved Only for training and service purposes ...

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