LG 55UN6900PUB Service Manual Download Page 19

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Normal

audio

Move to No

video/No audio

No video

Normal audio

Normal

voltage

Check Power Board 13.2V output

Normal

voltage

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

Error

symptom

A. Video error

No video/ Normal audio

☞

A18

☞

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 or EPI Cable, Speaker Cable, IR B/D Cable,,,)

Only for training and service purposes.

Summary of Contents for 55UN6900PUB

Page 1: ...f 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 2020 LG ...

Page 2: ... reserved Only for training and service purposes CONTENTS CONTENTS 2 SAFETY PRECAUTIONS 3 SERVICING PRECAUTIONS 4 SPECIFICATION 6 SOFTWARE UPDATE 9 BLOCK DIAGRAM 10 EXPLODED VIEW 11 ASSEMBLY DISASSEMBLY GUIDE 13 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: ... 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 Broadcasting system ATSC NTSC M 64 256 QAM 3 Available Channel VHF 02 13 UHF 14 69 DTV 02 69 CATV 01 135 CADTV 01 135 4 R...

Page 7: ...2160P Not Support for FHD 17 3840 2160 112 5 50 594 UDTV 2160P Not Support for FHD 18 3840 2160 134 86 59 94 593 4 UDTV 2160P Not Support for FHD 19 3840 2160 135 60 594 UDTV 2160P Not Support for FHD 20 4096 2160 53 95 23 98 296 7 UDTV 2160P Not Support for FHD 21 4096 2160 54 24 297 UDTV 2160P Not Support for FHD 22 4096 2160 56 25 25 297 UDTV 2160P Not Support for FHD 23 4096 2160 61 43 29 97 2...

Page 8: ...2 5 50 594 UDTV 2160P Not Support for FHD 28 3840 2160 134 86 59 94 593 4 UDTV 2160P Not Support for FHD 29 3840 2160 135 60 594 UDTV 2160P Not Support for FHD 30 3840 2160 225 100 1188 UDTV 2160P 4K120 model K6Hp HDMI 3 4 port O20 or 8K model 31 3840 2160 269 73 119 88 1186 8 UDTV 2160P 32 3840 2160 270 120 1188 UDTV 2160P 33 4096 2160 53 95 23 98 296 7 UDTV 2160P Not Support for FHD 34 4096 2160...

Page 9: ...About This TV page for update 5 TV is updating 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 Support Software Update 2 Click CHEK FOR UPDATES system check newest version 3 Click DOWNLOAD AND INSTALL 4 TV is updating 5 Afte...

Page 10: ... 8 lane Vx1 EPI CEDS FCIC SPI I2C 3 Main PMIC IF_S IF GST MCLK GCLK EO I2C 6 NVRAM 256Kb I2C_5 I2C 1 2 EPI block IQ IP HDMI4 2 0 depend on model TS EPI 60P 65 8 lane 55 6lane CEDS 68P Area OPT USB_WIFI 1 5V DDR 0 96V Core CP U 3 3V Normal 1 0V Eth 3 5V ST_BY 1 8V 5V Normal Sub PMIC 0 96V 1 5V 3 3V 5V 1V 1 8V 3 5V_ST 0 95V 1 5V 3 3V 13V 3 3V 5V 5V 1V 1 8V 1 8V 3 5V_ST 3 5V_ST 3 3V 3 5V_ST 3 5V_ST 1...

Page 11: ...cs 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 400 LV1 800 530 121 HP1 HS1 120 500 540 820 HW1 200P 200A LV2 570 901 902 952 951 AR1 700 A1...

Page 12: ...nc All rights reserved Only for training and service purposes EXPLODED VIEW MODULE MRC use only MRC Module Repair Center IMPORTANT NOTICE POL Front Panel Ass y POL Rear Optical Sheet Rear Side 200PPF 200PPR 200P 200PC 200SL1 200SR1 ...

Page 13: ... purposes ASSEMBLY DISASSEMBLY GUIDE SET Cover Rear 1 Put the set facedown on the table and remove whole screw 2 Push the cover rear by one hand and pull it upward by another hand 3 Doing the step 4 at the opposite side also It is easy to pull it if you put your finger in the groove ...

Page 14: ...ISASSEMBLY GUIDE MODULE Case Top Step 1 Main PSU SPK VESA Wifi IR disassemble Step 2 S PCB Cover Shield disassemble Step 3 LCM reverse and disassemble Source PCB from Holder Step 4 Case Top Screw disassemble side screw and Case Top disassemble Rear Sliver screw 5ea top 7ea side L 5ea side R 5ea down 7ea ...

Page 15: ...y for training and service purposes Step 5 Panel disassemble Step 6 Guide Panel disassemble Step 7 Optical Sheet disassemble DS Prism middle Prism down DP Step 8 DPS LED Fixer disassemble Reflector Sheet disassemble rotate DPS 6ea push LED fixer in back 3ea ...

Page 16: ...Bottom LED Array Assemble Step 1 Attach the Double Tape 1 Attach the Double Tape in Guide Line of Cover Bottom 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 NG OK Required LED Array Quantity Inch 55 Q ty EA ...

Page 18: ...off while viewing power auto on off 7 8 8 C Audio error No audio Normal video 9 9 Wrecked audio discontinuation noise 10 10 D Function error Remote control Local switch checking 11 MR19 operating checking 12 11 12 Wifi operating checking 13 13 External device recognition error 14 14 E Noise Circuit noise mechanical noise 15 15 F Exterior error Exterior defect 16 First of all Check whether there is...

Page 19: ...arts 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 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 or EPI Cable Spe...

Page 20: ...dio Check 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 Error symptom 2 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 21: ...ain B D Normal Picture Y N Y Close Y Close By using Digital signal level meter By using Diagnostics menu on OSD Advanced 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 Er...

Page 22: ...r 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 A28 A7 Standard Repair Process Established date Revised date Error symptom 4 Copyright 2020 LG Electronics Inc All rig...

Page 23: ...I 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 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 ...

Page 24: ...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 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 Error symptom 6 Stand By Red or Turn On Operating Turn Off Close Copyright 2020 LG Electronics Inc All rights reserved Only for training and service ...

Page 25: ...2 phase out Check A C cord Check for all 2 phase power out Check outlet Replace Main B D CPU Abnormal Replace Power B D N Y Normal End Established date Revised date Error symptom Standard Repair Process 7 Abnormal 1 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 26: ...Check fail after multi power on Check Change Power B D CPUABNORMAL If the CPU attempts to reset in case of abnormal operation and Shut Down in case of failure Check Change Main B D NO POLING Power off when receiving no ack RESULT TV power off on Reboot CONDITION There is no I2C response from CPU for 15 seconds Check Change Main B D CPUCMD Power off by main SoC command Check Change Main B D INV_ERR...

Page 27: ...ace Power Board and repair parts Check Speaker disconnection N Y Replace Speaker Replace MAIN Board End C Audio error No audio Normal video A21 A22 A18 Disconnection Established date Revised date Error symptom Standard Repair Process 9 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 28: ...ternal 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 13 2V Replace Main B D In case of External Input signal error Check and fix external device Replace Main...

Page 29: ...m Check 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 A23 Replace Main B D Y A22 Standard Repair Process Established date Revised date Error symp...

Page 30: ...dard Repair Process Established date Revised date Error symptom Replace MR20 Turn off on the set and press the wheel Press the Home Back key about 5sec Close If you conduct the loop at 3times change the MR20 Y Check the INSTART menu RF Receiver ver is 00 00 Y Check Repair RF assy connection N Change the RF Receiver assy Y RF Receiver ver is 00 00 N Close A24 A4 A4 12 Copyright 2020 LG Electronics ...

Page 31: ...r Wifi cable connection N Check the Wifi wafer 1pin Standard Repair Process Established date Revised date Error symptom 13 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 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 32: ... Check and fix 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 Error symptom Standard Repair Process 14 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 33: ...ceed as shown 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 Error symp...

Page 34: ...lace cabinet Replace remote control Remote control damage Stand dent Replace stand F Exterior defect Exterior defect Established date Revised date Error symptom Standard Repair Process 16 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 35: ...A5 6 A Video error _Vertical Horizontal bar residual image light spot Connection diagram A6 7 A Video error_ Color error Check Link Cable Vx1 EPI reconnection condition A7 8 Appendix Defected Type caused by T Con Inverter Module Check Cable 1 2 A 1 11 A 2 11 9 Exchange Main Board 1 3 A 3 11 A 5 11 10 Exchange Module 1 3 A 6 11 A 8 11 11 Exchange T Con 1 2 A 9 11 A 10 11 Only using T con model 12 E...

Page 36: ...o Normal video Checking method in menu when there is no audio A20 17 Voltage and speaker checking method when there is no audio A21 18 D Function error Remote control operation checking method A22 19 Motion Remote operation checking method A23 20 E Etc How to use the Service remote control A24 A26 21 Check items after Main B D replacement A27 22 Adjustment Test pattern ADJ Key A28 Continued from p...

Page 37: ... Content 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 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 38: ...ideo Normal audio A2 ALL MODELS Entry method 1 Press the ADJ button on the remote control for adjustment 2 Enter into White Balance 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 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 39: ...B 20dB etc 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 All Settings Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 40: ...eo 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 65UN81006LB Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 41: ...easuring each voltage 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 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 42: ...ical Horizontal 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 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 43: ...tion 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 43 49 55 65UN69 43 49 55 65UN71 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 44: ... 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 50 60UN69 50 60UN71 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 45: ...n of FFC cable CABLE R Color Excessive Color is Excessive due to FFC Cable Contact CABLE Screen darkness screen is dark due to poor contact due to disconnection of the FFC cable pin CABLE G Color Excessive G color transient due to poor FFC cable connection Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 46: ...lor spread FFC connection problem CABLE Color spread FFC connection problem CABLE Screen stop Due to foreign substance within FFC PIN Appendix Examples of Symptoms Image error Check for poor cable contact Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 47: ...Main Screen noise Broken screen due to Main IC problem Main Dark picture Dark left side screen Main Broken picture Top bottom screen part Picture problem due to tuner Inner side quality problem Appendix Examples of Symptoms Main Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 48: ...anner Main Screen spread Screen corner appears blurry Main Color Spread Color spread on the screen Main Blurry Screen Blurry picture on the screen Check parts by symptom Appendix Examples of Symptoms Main Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 49: ...n problem Right side screen problem Main LG logo Screen problem Screen picture spread problem Main Right side picture problem No problem at the initial stage During Heat run right side picture problem Check parts by symptom Appendix Examples of Symptoms Main Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 50: ...the screen MODULE Internal matter BLU internal foreign matter inflow MODULE Image broken 6 block image broken MODULE Image broken Screen sync signal broken A 6 11 Check parts by symptom Appendix Examples of Symptoms Module Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 51: ...ng due to lateral external impact and internal bending of BLU MODULE Vertical smear Vertical spreading on cube screen in no signal MODULE Over color Screen contour part brightly Over color A 7 11 Check parts by symptom Appendix Examples of Symptoms Module Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 52: ...nter of the screen 1 block dark MODULE Vertical bar Center Vertical Bar MODULE Darkness at the bottom of the screen MODULE internal BLU breakage A 8 11 Check parts by symptom Appendix Examples of Symptoms Module Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 53: ...ure below the screen is broken T CON screen lower image broken T Con is defective and the picture below the screen is broken T CON screen lower image broken T Con is defective and the picture below the screen is broken A 9 11 Check parts by symptom Appendix Examples of Symptoms Only if using T con Board Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 54: ...en Initial normal operation upper darkness during heat run T CON Image Broken The entire screen is dark and bit noise occurs T CON Image Broken The entire screen is dark and bit noise occurs A 10 11 Check parts by symptom Appendix Examples of Symptoms Only if using T con Board Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 56: ...k front Power 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 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 57: ...On Store Mode Power Check Sequence 1 AC input Check SK100 100 240Vac 2 PWR ON Check P201 1 pin SET On above 3V SET St by 0V 3 13 2V DC Check P201 4 8 pin SET On 13 2V SET St by 7 8V 4 MS Level Check P201 11 Pin 5 LED voltage Check P801 LED B Home mode General Customer Store mode use Store all condition meets Power Board OK Depending on Model Power Board is different But Interface P801 P201 and Spe...

Page 58: ...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 65UN81006LB K6LP Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 59: ...und 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 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 60: ...speaker 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 FT 2 SPK_R FT 3 SPK_L FT 4 SPK_L FT Copyright 2020 LG Electronics Inc A...

Page 61: ...al 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 EYE Sensor Pin Pin name 1 VCC 2 USB_DM 3 USB_DP 4 GND 5 WOL WIFI_ON 6 VCC 7 WIFI_Suspend Resume 8 GND 9 Combo_Reset 10 BT_WAKEUP_HOST 11 GND 12 VCC 13 14 15 16 EYE_SDA 17 EYE_SCL 18 GND 19 IR 20 LED_R 21 GND 22 VCC 23 KEY2 24 KEY1...

Page 62: ... 2 Check the 3 5V on the terminal 22 Checking order to check motion remote wifi Wifi BT Front Wifi BT Rear A23 Pin Pin name 1 VCC 2 USB_DM 3 USB_DP 4 GND 5 WOL WIFI_ON 6 VCC 7 WIFI_Suspend Resume 8 GND 9 Combo_Reset 10 BT_WAKEUP_HOST 11 GND 12 VCC 13 14 15 16 EYE_SDA 17 EYE_SCL 18 GND 19 IR 20 LED_R 21 GND 22 VCC 23 KEY2 24 KEY1 25 GND ALL MODELS Copyright 2020 LG Electronics Inc All rights reserv...

Page 63: ...use the Service remote control E Etc A24 Established date Revised date Error symptom Content A24 0 4 1 3 0 4 1 3 1 How to access the remote control 65UN81006LB K6LP Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

Page 64: ...a Zoom Aucto Screen 4 3 16 9 PSM Changes in the order of Bright Picture Easy Picture Cinema Spots Game Custom PIcture1 Custom Picture2 Bright Picture SSM Added Function Standard user music cinema sports game standard user PIP Picture In Picture is activated TEXT Access to the Power Only mode CAP Broadcasting caption on off MPX Stereo mode mono stereo foreign language access Used when in factory mo...

Page 65: ... Off White Red Green Blue Black Pattern Off Change X STUDIO Added function HDD USB external device s HDD screen is activated MENU User function gets activated EXIT Exit from the current mode TIME SHIFT Added function Moves forward backward of recorded contents MUTE Mute function 0 Volume IN STOP SET to factory mode VOL Volume Up Down CH Channel Up Down AV1 2 3 Added function Connects to external i...

Page 66: ...n the model name and serial number after checking the ID label on the back cover 1 Press the Service remote control instart Key 2 Press the Service remote control ADJ Key No 11 Select White Balance Record the R G B GAIN Cut value of the color temperature before main board replacement After replacing the main board key in the recorded value 65UN81006LB Copyright 2020 LG Electronics Inc All rights r...

Page 67: ...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 A28 Established date Revised date Error symptom Content A28 Copyright 2020 LG Electronics Inc All rights reserved Only for training and service purposes ...

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