LG 65UH8500 Service Manual

The LG 65UH8500 is a 65-inch 4K Ultra HD Smart LED TV with webOS 3.0, HDR Pro, Local Dimming, TruMotion 240Hz, Magic Remote compatibility, built-in Wi-Fi, HDMI 2.0 inputs, USB ports, HEVC decoding, and Smart TV features. This service manual provides technical information for qualified service personnel including disassembly instructions, troubleshooting guides, circuit diagrams, and replacement part information.

1. Product Overview 2. Technical Specifications 3. Disassembly Instructions 4. Main Board Replacement 5. Power Supply Board 6. LCD Panel Assembly 7. T-Con Board Service 8. Backlight System 9. Software Update Procedures 10. Troubleshooting Flowcharts 11. Parts List

Product Overview

Major components: Main board (EAX64936804), Power supply board (EAX64936801), T-Con board (6870C-0734A), LCD panel (LG Display), LED backlight strips, Wi-Fi module, IR sensor board, and control buttons.

Component	Part Number
Main Board	EAX64936804
Power Supply	EAX64936801
T-Con Board	6870C-0734A
LCD Panel	LG Display 65" UHD
Wi-Fi Module	6841T-1013A
IR Sensor Board	EAX64936802
LED Backlight Strips	Set of 12 strips
Stand Assembly	AKB74915601
Magic Remote	AN-MR650
Power Cable	AKB73755601

Technical Specifications

Screen Size: 65 inches Diagonal
Resolution: 3840 x 2160 (4K UHD)
Display Technology: IPS LED with Local Dimming
HDR: HDR10, Dolby Vision, HLG
Refresh Rate: TruMotion 240Hz
Smart Platform: webOS 3.0
Connectivity: 4x HDMI 2.0, 3x USB 2.0, Ethernet, Wi-Fi, Component, Composite
Audio: 20W (10W x 2) with Dolby Digital
Power Consumption: 180W typical, 0.3W standby
Power Supply: 100-240V AC, 50/60Hz

Disassembly Instructions

Required tools: Phillips screwdriver, plastic opening tools, anti-static wrist strap.

Remove stand: Lay TV face down on soft surface, remove screws securing stand.
Remove rear cover: Remove all screws from rear casing, use plastic tools to separate clips.
Disconnect cables: Carefully disconnect all ribbon cables and connectors.
Access internal boards: Remove shield covers to access main board, power supply, and T-Con board.

WARNING! Always disconnect power before disassembly. Handle LCD panel with care to avoid damage.

Main Board Replacement

Procedure for replacing main board (EAX64936804):

Disconnect all cables from main board including power, LVDS, and input cables.
Remove mounting screws securing main board to chassis.
Carefully lift main board out of TV chassis.
Install new main board and secure with screws.
Reconnect all cables ensuring proper orientation.
Test TV operation before reassembling.

NOTE: Main board replacement may require software update.

Power Supply Board

Power supply board (EAX64936801) provides voltages: 12V, 24V, 3.3V standby.

Voltage	Purpose	Test Point
12V	Main board operation	CN201 Pin 1-3
24V	LED backlight driver	CN202 Pin 1-2
3.3V STBY	Standby power	CN201 Pin 8
PS-ON	Power on signal	CN201 Pin 6
BL-ON	Backlight enable	CN201 Pin 7

CAUTION! High voltage present on power supply board even when unplugged.

LCD Panel Assembly

65-inch UHD IPS panel with LED edge lighting. Handle with extreme care during service.

Remove bezel: Carefully separate plastic bezel from front of panel.
Access panel: Remove diffuser sheets and optical films.
LED replacement: Replace individual LED strips if backlight failure occurs.
Reassembly: Ensure all optical components are properly aligned.

WARNING! LCD panel is fragile and expensive. Use proper handling techniques.

T-Con Board Service

T-Con board (6870C-0734A) located at top center of panel. Common symptoms of failure:

No picture but sound present
Vertical/horizontal lines on screen
Intermittent picture loss
Abnormal colors or patterns

Test voltages: VCC 12V, VGH 25V, VGL -7V, VCOM 6.5V

Backlight System

Edge-lit LED system with 12 LED strips. Backlight troubleshooting:

Check BL-ON signal from main board (3.3V when on)
Measure 24V supply to LED driver
Test individual LED strips for open circuits
Check current sensing resistors

LED Strip Replacement: Requires complete disassembly of LCD module.

Software Update Procedures

Methods for updating TV software:

USB Update: Download firmware to USB, insert in TV, follow on-screen prompts
Online Update: Network > Software Update > Check for Updates
Service Menu: Using service remote to force update
ISP Update: Using computer and RS-232 cable for factory programming

NOTE: Do not interrupt power during software update.

Troubleshooting Flowcharts

Symptom	Diagnostic Steps	Solution
No Power	Check AC input, standby voltage, PS-ON signal	Replace power supply board
No Picture/Sound	Test main board voltages, check processor operation	Replace main board
No Picture with Sound	Check T-Con voltages, test backlight operation	Replace T-Con board or backlight
Intermittent Operation	Check for loose connections, overheating components	Reseat cables, replace faulty board
Wi-Fi Not Working	Test Wi-Fi module, check antenna connection	Replace Wi-Fi module or main board

Parts List

Part Description	Part Number	Qty
Main Board Assembly	EAX64936804	1
Power Supply Board	EAX64936801	1
T-Con Board	6870C-0734A	1
LCD Panel Complete	LG Display 65UHD	1
LED Backlight Strips Set	6841T-1022A	12
Wi-Fi Module	6841T-1013A	1
IR Sensor Board	EAX64936802	1
Stand Assembly	AKB74915601	1
Magic Remote	AN-MR650	1
Screw Set	AKB73755602	1

Ordering: Contact LG Parts Department or authorized distributors.