LED TV - Service Manual - Chassis UA62F - Model 75UH6550 75UH6550-UB

Oct 23, 2026

Uploaded by Elsa

LED TV service manual for chassis UA62F, covering model 75UH6550 and 75UH6550-UB. The document provides safety precautions for servicing, including isolation transformer guidance, correct replacement of special safety components, and cautions on fuse and high-wattage resistor handling. It explains AC leakage current cold and hot checks using specified measurement setups and acceptable resistance/voltage limits, emphasizing shock hazard prevention. It also lists general servicing precautions like unplugging before disassembly, proper high-voltage measurement, and safe contact cleaning instructions.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages139

Reading Time5 h 50 min

AccessFree to download

Contents

Safety precautions

Servicing precautions

Specification

Adjustment instruction

Block diagram

Exploded view

Assembly / Disassembly

Schematic circuit diagram

Troubleshooting guide

Internal Use Only LED TV SERVICE MANUAL CHASSIS : UA62F MODEL : 75UH6550 75UH6550-UB CAUTION BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. P/NO : MFL69460606 (1603-REV00) CONTENTS CONTENTS .............................................................................................. 2 SAFETY PRECAUTIONS ........................................................................ 3 SERVICING PRECAUTIONS ................................................................... 4 SPECIFICATION ...................................................................................... 6 ADJUSTMENT INSTRUCTION .............................................................. 13 BLOCK DIAGRAM.................................................................................. 25 EXPLODED VIEW .................................................................................. 34 ASSEMBLY / DISASSEMBLY ............................................................... 35 SCHEMATIC CIRCUIT DIAGRAM ........................................... APPENDIX TROUBLE SHOOTING GUIDE ................................................ APPENDIX Copyright © LG Electronics. Inc. All rights reserved. -2- LGE Internal Use Only Only for training and service purposes SAFETY PRECAUTIONS IMPORTANT SAFETY NOTICE Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by in the Schematic Diagram and 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. General Guidance An isolation Transformer should always be used during the servicing of a receiver whose chassis is not isolated from the AC power line. Use a transformer of adequate power rating as this protects the technician from accidents resulting in personal injury from electrical shocks. It will also protect the receiver and it's components from being damaged by accidental shorts of the circuitry that may be inadvertently introduced during the service operation. If any fuse (or Fusible Resistor) in this TV receiver is blown, replace it with the specified. When replacing a high wattage resistor (Oxide Metal Film Resistor, over 1 W), keep the resistor 10 mm away from PCB. Keep wires away from high voltage or high temperature parts. Before returning the receiver to the customer, always perform an AC leakage current check on the exposed metallic parts of the cabinet, such as antennas, terminals, etc. , tobe sure the 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 antenna terminals, phone jacks, etc. If the exposed metallic part has a return path to the chassis, the measured resistance should be between 1 MΩ and 5.2 MΩ . 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. Leakage Current Hot Check (See below Figure) Plug the AC cord directly into the AC outlet. Do not use a line Isolation Transformer during this check. Connect 1.5 K / 10 watt resistor in parallel with a 0.15 uF capacitor between a known good earth ground (Water Pipe, Conduit, etc. ) and the exposed metallic parts. Measure the AC voltage across the resistor using AC voltmeter with 1000 ohms/volt or more sensitivity. Reverse plug the AC cord into the AC outlet and repeat AC voltage measurements for each exposed metal

FAQs

What is the key safety requirement before servicing this TV chassis?

Read and follow the safety precautions in the manual before servicing the chassis. Replace special safety-related components only with the same components recommended in the manual.

How is the AC leakage current cold check performed?

Remove the AC plug from the source, jumper the two plug prongs, switch on, then measure resistance from the AC plug prongs to exposed metallic parts. Acceptable results are 1 MΩ to 5.2 MΩ when there is a return path, and infinite when there is no return path.

What limits apply during the leakage current hot check?

Connect the TV directly to the AC outlet, place a specified resistor/capacitor network between earth ground and exposed metallic parts, and measure AC voltage. Any measured value must not exceed 0.75 volt RMS (corresponding to 0.5 mA); otherwise the set must be checked and repaired before returning to the customer.

Oct 23, 2026

Uploaded by Elsa