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LG 70UN7370AUD Service Manual
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LG 70UN7370AUD Service Manual

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LED TV
SERVICE MANUAL
CHASSIS : UAX3D
MODEL : 70UN7370AUD
MODEL :
MODEL :
CAUTION
BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.
P/NO : MFL71703813 (2002-REV00)
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 © 2020 LG Electronics Inc. All rights reserved. Only training and service purposes.
70UN7370PUC
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  • Page 1 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.
  • Page 2 SOFTWARE UPDATE ................9 BLOCK DIAGRAM ................. 10 EXPLODED VIEW .................. 11 ASSEMBLY / DISASSEMBLY GUIDE ........... 12 TROUBLE SHOOTING GUIDE ..........APPENDIX - 2 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 3: Safety Precautions

    When the exposed metal has no return path to the chassis the reading must be infinite. An other abnormality exists that must be corrected before the receiver is returned to the customer. - 3 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 4: Servicing Precautions

    - 4 - Copyright © LG Electronics Inc. All rights reserved. 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. Only for training and service purposes.

  • Page 6: Specification

    AV and DVI use same jack ; SPDIF out Optical Audio out Rear (1EA), HeadPhone HeadPhone out USB Input EMF, DivX HD, For SVC (download) JPEG, MP3, DivX HD - 6 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 7 25.12 SDTV 480P 720*480 31.47 59.94 SDTV 480P 720*480 31.5 27.02 SDTV 480P 720*576 31.25 SDTV 576P 1280*720 44.96 59.94 74.17 HDTV 720P - 7 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 8 8K Model Only. 7680*4320 1188 8K Model Only. 7680*4320 2376 8K Model Only. 7680*4320 263.74 59.94 2376 8K Model Only. 7680*4320 2376 8K Model Only. - 8 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 9: Software Update

    (5) After finished the update, below Pop-up appear (6) Turn OFF the TV and On. Check the updated SW Version and Tool Option - 9 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 10: Block Diagram

    BLOCK DIAGRAM - 10 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 11 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. - 11 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 12 1. Set B/C Guide 1-1. Allowed to handle Guide line 1-2. Prohibited while handling DO NOT handle the area all the time Guide line - 12 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 13: Disassembly Guide

    3. Unfasten screw on each points. 4. Lift up the rear cover using stuffs like paddle or cards to insert between rear cover and rear cover, bottom. 2pole - 13 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 14 8. Unfix the latch before disassembling rear cover, bottom. - use tools (pen or screw driver etc.) to push the latch 9. Unfasten screws on 2pole supporter 4 / 4 - 14 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 15: Assembly Guide

    3. Fasten screws on each points. 4. Hang speaker cable as below. 5. Workers should hold each side as below.(SHOULD check handling guide on first page.) - 15 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 16 Overlaps with case top B/C has been inserted 7. Fasten screws on each points. 8. Assemble 2pole stand. (A/B) 9. Fasten screws on each points. (A/B) - 16 - Copyright © LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 17 2) Disassemble 8 SPCB Cover shield L/R screws (Use M3 Screw Module Driver) 3) Disassemble the screw, and then move each SPCB cover field L/R upward to disassemble it. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 18 - Screw Spec : M3*6.0mm Tapping Screw(Silver) - Location : Up(11ea)/Left(6ea)/Right(6ea) - Driver : Normal size screw TIP Driver is available. Back side Screw point Left Right Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 19 7) Disassemble 4 EMI Tapes of the Panel SPCB - Remove parts attached to the cover Bottom by hand (no need to be removed up to the panel SPCB attachment surface) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 20 - Must be worked more than two people, one on the left and one on the right side with both hands reverse 180 degrees. Lift the lower SPCB Reverse Product Upper upwards Side Use as Support Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 21 - Unhook the C/Top hook fastened to the Guide Panel by using the flathead Driver. Insert Flathead Driver Section of C/Top Hook C/Top Hook (Up : 10ea , Left : 3ea, Right :3ea (Total 16ea) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 22 - After releasing the 4 sided Hook, remove the C/Top by lifting it upwards (* Precautions : Must be worked more than 2 people, Be careful of damage to the Case Top due to large size) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 23 (* Precautions : Must be worked more than 2 people, Be careful of damage to the Guide Panel due to large size) Up: 12ea, Down: 12ea, Left: 7ea, Right: 7ea Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 24 - Assembly direction is divided by the shape of the Sheets/Diffuser Plate on the front left side of SET (other than that, the corners are rectangular) Sheet 2ea+ Diffuser Plate: Chamfer shape Lower Sheet: Round shape the upper left Diffuser Plate1ea Upper Sheet: Chamfer shape SET Front Position Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 25 - Invert the LCM and disassemble the upper Support Pin Hook at the rear of the LCM using the tool (Long nose plier ) Backside Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 26 - Disassemble the Led Array Bar (Led Array and Cover Bottom are fixed with two-sided tape, so use appropriate force to cover the Led Array. Take it off and attach a new Led Array Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 27 - Align the reflector with the reflector guide hole at two locations on the center/bottom of the reflector and assemble two support plates first. Support DP assembly Center Up/Down Reflector Assemble. Align Guide Hole Support Plate Assemble Only 2 sites first Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 28 Support DP is vertical Position to the LCM. 26) Support Pins Assembly - Press the Support Pin with your hand down to fix it to the Cover Bottom (Total 5ea) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 29 * Precautions: Check that the sheet hanging hole on the upper/lower/left/right outer is properly seated on the cover Bottom Sheet hanging. Up : 8ea, Down : 6ea, Left : 5ea, Right : 5ea Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 30 As this may be relatively difficult, assemble as follows: G/Panel Forcing Force on Lower Side * Precautions : In case of gap between guide panel and sheet (Direction Down Line) Recheck Hook Tightening Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 31 - When the panel is seated, the guide panel should not be lifted onto the PG section. Panel damage occurs when assembling the case top while the panel is mounted on top of the PG. Guide Panel PG Guide Panel PG Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 32 31) Confirm C/Top Book Tightening - Check if the Hook is engaged C/Top Hook (Down: 8ea) C/Top Hook (Up: 10ea , Left: 3ea, Right:3ea (Total 16ea) ) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 33 33) Assemble the Panel SPCB L/R to the SPCB Holder. - First, enter the upper part of the holder and then press the lower part of the holder to tighten the SPCB. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 34 - Driver : M3 Screw Module Driver available. 35) Assemble 4 Panel SPCB EMI Tapes - Press EMI Tape attached to Panel SPCB side on Cover Bottom and attach it by hand.. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 35 - Screw Spec : M3*6.0mm Tapping Screw(Silver) - Location : Up(11ea)/Left(6ea)/Right(6ea) - Driver : Normal size screw TIP Driver is available. Backside Screw point 상 좌 우 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 36 39) Assemble 8 SPCB Cover shield L/R screws ( Use M3 Screw module Driver) *Precautions : Cover Shield flange must be inserted between C/Top and BLU (do not protrude into C/Top outer) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.

  • Page 37: Troubleshooting Guide

    TROUBLE SHOOTING GUIDE Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 38 E. Noise Circuit noise, mechanical noise F. Exterior error Exterior defect First of all, Check whether there is SVC Bulletin in GSCS System for these model. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 39 ☞A4 & A2 Always check & record S/W Version and White Replace Main Board Re-enter White Balance value Balance value before replacing the Main Board Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 40 ☞A18 Check various Check and No Video/ voltages of Power Normal replace No audio Board (13.2V…) voltage? MAIN B/D Replace Power Board and repair parts Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 41 1. Reconnection 2. Install Booster S/W Upgrade Contact with signal distributor Normal or broadcaster (Cable or Air) Picture? Normal Picture? Replace Main B/D Close Close Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 42 Component device/ Cable cable error normal Request repair for external device/cable Check external External HDMI device and Replace Main/T-con B/D device/ Cable error cable normal Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 43 Replace screen? HDMI/ Screen (Check normal operation of Main /T-con External Input, Component, normal? RGB and HDMI/DVI by connecting Jig, pattern Generator ,Set-top Box etc. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 44 Measure voltage of each output of Power B/D Normal? Normal Replace Main B/D voltage? Normal Check ST-BY 7.8V Close voltage? ☞A18 Replace Power B/D Replace Power Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 45 Error? Normal? Abnormal Check for all 3- phase Replace Power B/D power out Abnormal Fix A/C cord & Outlet and check each 3 phase out Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 46 Reboot by SW down load function UNKNOWN No meaning (same as initial value) COMP_END OLED threshold voltage degradation(Compensation) completes. PNWASHDONE Power off by panel noise wash function complited. (OLED) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 47 13.2V of Power Screen normal voltage Speaker off Board Cancel OFF Replace Power Board and repair parts Check Replace MAIN Board Disconnection Speaker disconnection Replace Speaker Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 48 (In case of Connect and check Normal External Input other external audio? signal error) device Check and fix external device Check and fix external device Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 49 Replace Main B/D (Power B/D don’t have problem) If R/C operate, Normal Close operating? Explain the customer cause is interference from light in room. Replace R/C Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 50 RF Receiver ver about 5sec Close is “00.00”? Replace MR20 Close Change the RF Receiver assy * If you conduct the loop at 3times, change the MR20. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 51 1pin Main B/D INSTART menu “NG”? ☞A24 Close Check & Repair Wifi cable connection ☞A4 Wi-Fi Mac value Close is “NG”? Change the Wifi assy Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 52 Recognition error - S/W Version HDMI/ Check and fix DVI, Optical Replace Main B/D Fix in Recognition external device/cable accordance error with technical information Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 53 “Part related to nose” in the Owner’s then proceed as shown in the solution manual Manual. (For models without any fix information, provide the description) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 54 Revised date Zoom part with Module Replace module exterior damage damage Cabinet Replace cabinet damage Remote Replace remote control control damage Stand Replace stand dent Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 55 Exchange Module (1) ~ (3) Inverter/ Module A-8/11 A-9/11 ~ Only using Exchange T-Con (1) ~ (2) T-con model A-10/11 Exchange Power Board(PSU) A-11/11 Continue to the next page Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 56 Motion Remote operation checking method How to use the Service remote control A24-A26 E. Etc Check items after Main B/D replacement Adjustment Test pattern - ADJ Key Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 57 Check LCD back light with naked eye Content date After turning on the power and disassembling the case, check with the naked eye, whether you can see light from locations. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 58 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 59 All Setting  Programmes  Programme Tuning & Settings  Manual Tuning All Settings When the signal is strong, use the attenuator (-10dB, - 15dB, -20dB etc.) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 60 Version checking method Content date <ALL MODELS> 1. Checking method for remote control for adjustment 65UN81006LB Version Press the IN-START with the remote control for adjustment Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 61 1. Check the signal strength or check whether the screen is normal when the external device is connected. 2. After measuring each voltage from power supply, finally replace the MAIN BOARD. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 62 Revised Content connection diagram (1) date <ALL MODELS> As the part connecting to the external input, check the screen condition by signal Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 63 A. Video error_Color error symptom date Revised Content Check Link Cable(Vx1/EPI) reconnection condition date 43/49/55/65UN73 Check the contact condition of the Link Cable, especially dust or mis insertion. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 64 A. Video error_Color error symptom date Revised Content Check Link Cable(Vx1/EPI) reconnection condition date 50/60UN73 Check the contact condition of the Link Cable, especially dust or mis insertion. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 65 A. Video error_Color error symptom date Revised Content Check Link Cable(Vx1/EPI) reconnection condition date 70UN73 Check the contact condition of the Link Cable, especially dust or mis insertion. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 66 Screen darkness to disconnection of the FFC cable pin. G color transient due to poor FFC cable CABLE G Color Excessive connection A - 1/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 67 CABLE Color spread FFC connection problem CABLE Color spread FFC connection problem Due to foreign substance within CABLE Screen stop FFC PIN A - 2/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 68 Main IC problem Main Dark picture Dark left-side screen Top/bottom screen part Main Broken picture Picture problem due to tuner Inner side quality problem A - 3/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 69 Screen spread Screen corner appears blurry Main Color Spread Color spread on the screen Main Blurry Screen Blurry picture on the screen A - 4/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 70 Screen picture spread problem Screen problem No problem at the initial stage. Right-side Main During Heat run, right-side picture picture problem problem A - 5/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 71 BLU internal foreign matter inflow MODULE Internal matter 6 block image broken MODULE Image broken MODULE Image broken Screen sync signal broken A - 6/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 72 BLU Vertical spreading on cube screen in no MODULE Vertical smear signal MODULE Over color Screen contour part brightly Over color A - 7/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 73 Center of the screen 1 block dark MODULE Screen darkness MODULE Vertical bar Center Vertical Bar Darkness at the MODULE bottom of the MODULE internal BLU breakage screen A - 8/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 74 T-Con is defective and the picture below T-CON image broken the screen is broken A - 9/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 75 The entire screen is dark and bit noise T-CON Image Broken occurs The entire screen is dark and bit noise T-CON Image Broken occurs A - 10/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 76 Appendix : Exchange Power Board (PSU) No Light No picture/Sound Ok A - 11/11 Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 77 Established B. Power error _No power symptom date Revised Content Check front Power Indicator date 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 78 SK100 (AC input) 273.6V 334.4V ※ Depending on Model Power Board is different. all condition meets, Power Board OK. But Interface(P801, P201) and Spec is same Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 79 <ALL MODELS> 65UN81006LB K6LP Entry method 1. Press the IN-START button of the remote control for adjustment. 2. Check the entry into adjustment item 3. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 80 1. Press the Setting button on the remote control 2. Select the Sound function of the Menu 3. Select the Sound Out 4. Select TV Speaker Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 81 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 © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 82 2. Check the standby 3.5V on the terminal 6 pin. (③) 3. AS checking the Pre-Amp(IR LED light), the power is in ON condition, an Analog Tester needle should move slowly, otherwise, it’s defective. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 83 Checking order to check motion remote/wifi KEY1 Checking order 1. Check BT/Wifi cable condition between BT/Wifi assy & Main board. 2. Check the 3.5V on the terminal 22. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 84 Error Established E. Etc symptom date Revised Content How to use the Service remote control date 1. How to access the remote control 65UN81006LB K6LP Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 85 Digital EYE function ON/OFF For some Model, access to the Test Pattern TILT Used for screen tilting change (Access to the old PDP control mode) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 86 Connects to external input 1,2,3 COMP1,2 (Added function) Connects to Component 1,2 HDMI1,2,3,4 Connects to HDMI 1,2,3,4 (Add function) DVI (Add function) Connects to DVI Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 87 - 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. Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.
  • Page 88 You can view 9 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!) Copyright © 2020 LG Electronics Inc. All rights reserved. Only for training and service purposes.

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