LG 75NANO91TPA Service Manual

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LED TV

SERVICE MANUAL

CHASSIS : UB12A

MODEL : 75NANO91TPA / TPZ

MODEL :

CAUTION

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

P/NO : MFL71795610 (2101-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.

75NANO91VPA

Summary of Contents for LG 75NANO91TPA

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 SPECIFICATION ..................6 SOFTWARE UPDATE ................9 BLOCK DIAGRAM ................. 11 EXPLODED VIEW .................. 12 ASSEMBLY / DISASSEMBLY GUIDE ........... 13 TROUBLE SHOOTING GUIDE ..........APPENDIX - 2 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 3 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 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 training and service purposes.
Page 6 * Some models do not support HDMI 4. USB Input My Media(Movie/Photo/Music List) or SVC SPDIF out Optical Audio out Headphone out All input * Depends on the model Ethernet Connect - 6 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 7 107.89 23.98 1188 7680*4320 1188 7680*4320 1188 7680*4320 131.87 29.97 1188 8K Model Only. 7680*4320 1188 7680*4320 2376 7680*4320 263.74 59.94 2376 7680*4320 2376 - 7 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 8 UHD DeepColor is On (UHD, 8K 120Hz models only), 2560*1440 182.99 119.99 497.7 Support only when UHD Deep- Color is On - 8 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 9 (6) After finishing the update, it will show a pop-up below the picture. (7) Click “Yes” : Tv will be turn off and on itself - 9 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 10 “The latest version of the SW is available for your TV. Do you want to update now” (3) [Yes] : update starts. [No] : Close the pop-up, check out later - 10 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 12 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. - 12 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 13 [Back Cover Disassembly Guide] (1) Lay the TV Set on a flat pad. (Disassemble Stand Assy) 75” (2) Disassemble B/C Screw Screw : 18EA - 13 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 15 (7) Remove the Latch 4EA and Back Cover by holding the center of the lower back cover and pushing it upwards as shown in the picture. Latch 2EA CAREFUL Latch 2EA CAREFUL - 15 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 16 1. Hold the left/right ends of the ‘Cover, Rear Bottom’ as shown in the picture. 2. Disassemble each latch on the left and right by twisting the bottom of the product. - 16 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 17 ▪ scene of b/c dent occurrence. When turning B/C for line input after holding the back of b/c, a dent occurs when tilting in a one-sided direction. - 17 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 20 * Be careful not to press the spcb when turning the module over. Case Top Screw * Case Top screw (6ea) * Down hooks (14ea) - 20 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 21 Then remove the LED Array. * When separating the LED array, hold the connector of the extension board with your hand and separate the LED array. - 21 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 22 * Assemble the reflectors in this order. (Right(Down) → Left(Up)). And when assembling the corner, please assemble so that the part marked Up is visible on the top. Center Part Corner Part - 22 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 23 ■ Step 5 Refer to the disassembly procedure in the previous chapter and assemble in reverse order from Step 6 to Step 1. * Be careful not to break the panel in each assembly step. - 23 - Copyright © LG Electronics Inc. All rights reserved. Only training and service purposes.
Page 25 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 26 ☞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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 27 ☞A18 Check and Check various Normal No Video/ replace voltages of Power No audio voltage? Board (13.2V…) MAIN B/D Replace Power Board and repair parts Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 28 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 29 Replace Main/T-con B/D error normal cable Request repair for external device/cable Check external External HDMI device and Replace Main/T-con B/D device/ Cable error cable normal Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 30 Replace screen? HDMI/ Screen (Check normal operation of Main /T-con normal? External Input, Component, RGB and HDMI/DVI by connecting Jig, pattern Generator ,Set-top Box etc. Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 31 Measure voltage of each output of Power B/D Normal? Normal ☞A18 Replace Main B/D voltage? Normal Check ST-BY 7.8V Close voltage? Replace Power B/D Replace Power Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 32 Replace Main B/D Normal? Error? Abnormal Check for all phase Replace Power B/D Abnormal power out Fix A/C cord & Outlet and check each phase out Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 33 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 34 Power Board Screen normal voltage Speaker off Cancel OFF Replace Power Board and repair parts Check Replace MAIN Board Disconnection Speaker disconnection Replace Speaker Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 35 (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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 36 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 37 “00.00”? Replace MR21 Close Change the RF Receiver assy Or RF Receiver Cable * If you conduct the loop at 3times, change the MR21. Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 38 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 39 Recognition error - S/W Version HDMI/ DVI, Optical Check and fix Replace Main B/D Fix in Recognition external device/cable accordance error with technical information Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 40 “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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 41 Revised date Zoom part with Module Replace module exterior damage damage Cabinet Replace cabinet damage Remote control Replace remote control damage Stand Replace stand dent Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 42 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 43 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 44 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 45 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 46 All Setting  General  Programmes  Programme Tuning & Settings  Manual Tuning When the signal is strong, use the attenuator (-10dB, -15dB, -20dB etc.) Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 47 Version checking method Content date <ALL MODELS> 1. Checking method for remote control for adjustment Version RELEASE Press the IN-START with the remote control for adjustment Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 48 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 49 Revised Content connection diagram (1) date <ALL MODELS> As the part connecting to the external input, check the screen condition by signal Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 50 A. Video error_Color error symptom date Revised Content Check Link Cable(Vx1/EPI) reconnection condition date Check the contact condition of the Link Cable, especially dust or mis insertion. Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 51 CABLE Screen darkness disconnection of the FFC cable pin. G color transient due to poor FFC cable CABLE G Color Excessive connection A - 1/11 Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 52 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 53 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 54 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 55 Screen picture spread problem Screen problem No problem at the initial stage. Right-side picture Main During Heat run, right-side picture problem problem A - 5/11 Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 56 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 57 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 58 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 60 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 62 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 63 - SET On : above 3V - SET St-by : 0V 5. LED voltage Check : P203, 1~4 pin All condition meets, Power Board OK. SK100 (AC input) Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 64 <ALL MODELS> RELEASE Entry method 1. Press the IN-START button of the remote control for adjustment. 2. Check the entry into adjustment item 3. Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 65 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 66 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 67 2. Check the standby 3.5V on the terminal 22 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 68 Checking order 1. Check BT/Wifi cable condition between BT/Wifi assy & Main board.(Check ① and ②.) 2. Check the 3.5V on the terminal 1. (③) Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 69 Standard Repair Process Detail Technical Manual Error Established E. Etc symptom date Revised Content How to use the Service remote control date 1. How to access the remote control RELEASE Copyright © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 70 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 71 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 72 - 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.
Page 73 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 © 2021 LG Electronics. Inc. All rights reserved. Only for training and service purposes.

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LG 75NANO91TPA Service Manual

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