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File name LG_42LG30R-MA.pdf

Internal Use Only website:http://biz.LGservice.com LCD TV SERVICE MANUAL CHASSIS : LP81A MODEL : 42LG30R CAUTION 42LG30R-MA BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. CONTENTS CONTENTS ... 2 SAFETY PRECAUTIONS ...3 SPECIFICATION ...4 ADJUSTMENT INSTRUCTION ...11 TROUBLE SHOOTING ...15 BLOCK DIAGRAM...20 EXPLODED VIEW ... 21 SVC. SHEET ... Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes -2- LGE Internal Use Only 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 Replacement Parts List. 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 1W), keep the resistor 10mm away from PCB. Keep wires away from high voltage or high temperature parts. 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 1.5K/10watt resistor in parallel with a 0.15uF 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 0.5mA. In case any measurement is out of the limits specified,