LG 32LJ500U ZB NT72461 Service Manual

LED TV

SERVICE MANUAL

Chassis:

NT72461

MODEL:

32LJ500U-ZB_43LJ500V-ZB(EU)

32LJ503U-ZA_43LJ503V-ZA(CIS)

32LJ503U-ZA_43LJ503V-ZA(RU)

CAUTION

BEFORE SERVICING THE CHASSIS,

READ THE SAFETY PRECAUTIONS IN THIS MANUAL

1

Copyright

ⓒ

2017 LG Electronics. Inc. All right reserved.

Only for training and service purposes

Internal Use Only

LGE Internal Use Only

CONTENTS

CONTENTS ………………………………………………………………………………………………….....2 SAFETY PRECAUTIONS………………………………………………………………………………….…..3 SERVICING PRECAUTIONS……………………………………………………………………………….…4 SPECIFICATION………………………………………………………………………………………………...7 SOFTWARE UPGRADE PROCEDURE…………………………………………………………………….10 BLOCK DIAGRAM……………………………………………………………………………………………12 EXPLODED VIEW…………………………………………………………………………………………….13 PRODUCT DISASSEMBLY PROCESS……………………………………………………………………17 TROUBLE SHOOTING GUIDE .......................................................................................APPENDIX 21 ADJUSTMENT INSTRUCTION……………………………………………………………………………...49

SAFETY PRECAUTIONS

IMPORTANTSAFETY NOTICE

Many electrical and mechanical parts in this chassis have special safety-related characteristics . These parts are identified by in the 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, orother Hazards

Donot modify the original design without permission of manufacturer +

General Guidance

An is olation 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., to be 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.

Another 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 metallic part. Any voltage measured must not exceed 0.75 volt RMS which is corresponds to

1.5 mA.

In case any measurement is out of the limits specified, there is possibility of shock hazard and the set must be checked and repaired before it is returned to the customer.

Leakage Current Hot Check circuit

When 25Ais impressed between Earth and 2nd Ground *Base on Adjustment standard

SERVICING PRECAUTIONS

CAUTION: Before servicing receivers covered by this service manual and its supplements and addenda, read and follow the SAFETY PRECAUTIONS on page 3 of this publication.

NOTE: If unforeseen circumstances create conflict between the following servicing precautions and any of the safety precautions on page 3 of this publication, always follow the safety precautions. Remember: Safety First.

General Servicing Precautions

1. Always unplug the receiver AC power cord from the AC power source before;

a. Removing or reinstalling any component, circuit board module or any other receiver assembly.

b. Disconnecting or reconnecting any receiver electrical plug or other electrical connection.

c. Connecting a test substitute in parallel with an electrolytic capacitor in the receiver.

CAUTION: A wrong part substitution or incorrect polarity installation of electrolytic capacitors may result in an explosion hazard.

2. Test high voltage only by measuring it with an appropriate high voltage meter or other voltage measuring device (DVM, FETVOM, etc) equipped with a suitable high voltage probe. Do not test high voltage by "drawing an arc".

3. Do not spray chemicals on or near this receiver or any of its assemblies.

4. Unless specified otherwise in