LG OLED55B9PUA

P/NO : MFL71409504 (1903-REV00)
CHASSIS : EA92B
MODEL : OLED55B9PUA
MODEL : OLED65B9PUA
OLED 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.

LG OLED55B9PUA Specifications

General

Screen Type	oled
Wall Mount	300mm x 200mm
Features	4k upscaling, true color accuracy, infinite contrast, perfect black, billion rich colours
Tuner	digital
Screen Size	54.6 inches, 55 inches
Resolution	4k (2160p)
Refresh Rate	120hz
Closed Captioning	yes
HDR	yes
HDR Format	dolby vision, hdr 10, hybrid log-gamma (hlg)
Built-In Speakers	true, front firing
Surround Sound	dts-hd, dolby atmos
Speakers Output	40 watts
HDMI ARC Ports	yes
USB Ports	3
USB 2.0 Ports	3
Ethernet	yes
RF Antenna	yes
Bluetooth	true, 5.0
Network	built-in wi-fi, ethernet
Headphones Output	yes
Digital Optical Audio Outputs	1
Component Video Inputs	0
Composite Video Inputs	1
DVI	0
SmartTV	webos
Smart Applications	amazon alexa, apple homekit, google assistant
Voice Assistant	amazon alexa, google assistant
Remote Control	magic
3D	no
Power Consumption	202 kilowatt hours
Depth with Stand	9.7 inches
Height with Stand	29.2 inches
Width with Stand	48.4 inches
Net Weight with Stand	43.9 pounds
Depth without Stand	1.8 inches
Height without Stand	27.7 inches
Net Weight without Stand	41.7 pounds

Summary

Safety Precautions

Important Safety Notice

Essential safety precautions for replacing parts to prevent hazards like shock or fire.

General Servicing Guidance

General guidelines for safe servicing, including isolation transformers and wire placement.

Leakage Current Checks

Procedures for performing AC leakage current checks (Cold and Hot).

Servicing Precautions

General Servicing Precautions

Precautions for unplugging the receiver, testing high voltage, and cleaning contacts.

Electrostatically Sensitive (ES) Devices

Techniques to reduce damage to ES devices from static electricity.

General Soldering Guidelines

Guidelines for using grounded-tip irons, solder types, and cleaning tips.

Component Removal and Replacement

Procedures for replacing ICs, transistors, diodes, fuses, and resistors.

Circuit Board Foil Repair

Techniques for repairing damaged copper patterns on circuit boards.

Specifications

Application Range and Test Conditions

Defines scope, environmental, and electrical conditions for testing.

Test Methodologies

Outlines performance and safety testing methods.

General Specifications

Lists overall technical specifications for the TV.

External Input Support Formats

Details supported resolutions and formats for HDMI and DTV inputs.

Software Update

USB Update Procedure

Steps for updating TV software using a USB memory stick.

Network Update (NSU)

Procedure for updating TV software via Network (NSU).

Block Diagrams

Main IC Block Diagram

Overview of the main components and their interconnections.

I2 C and Tuner Diagrams

Illustrates I2C bus and tuner signal paths.

Video, Audio, and HDMI Diagrams

Shows connections for video, audio inputs, and HDMI ports.

USB, Wi-Fi, and Other Interfaces

Block connections for USB, Wi-Fi, M-Remote, and UART.

Exploded View

Part Identification and Safety

Visual breakdown of components with safety precautions.

Disassembly Guide

Stand Cover and Back Panel Removal

Steps to remove stand cover and main back panel.

Component and Cable Removal

Procedures for removing Wifi/Jog, IR, cables, and speakers.

PCB and Bracket Removal

Instructions for removing Main PCB, PSU, and VESA bracket.

Troubleshooting Guide

Video Error: No VideoNormal Audio

Troubleshooting steps for no video or normal audio symptoms.

Video Error: Picture Issues

Diagnosing picture broken, freezing, or color errors.

Video Error: External Device Color

Diagnosing color issues related to external input devices.

Power Error: No Power

Steps to troubleshoot when the TV does not power on.

Power Error: Intermittent Power

Troubleshooting for unexpected power off during use or auto power cycling.

Power Error: Power Off Modes

Analyzing specific power-off codes for diagnosis and repair.

Audio Error: No Audio

Diagnostic steps for when there is no audio but video is present.

Audio Error: NoiseDisruption

Troubleshooting steps for distorted, discontinuous, or noisy audio.

Function Error: Remote Control

Diagnosing problems with remote control or local buttons.

Function Error: Wi-FiDevice Recognition

Troubleshooting Wi-Fi issues and external device recognition.

Noise Troubleshooting

Steps to identify and resolve circuit or mechanical noise problems.

Exterior Defect Diagnosis

Procedures for diagnosing and addressing external physical damage.