LG RU-20LA61 Service Manual

LCD TV

SERVICE MANUAL

CAUTION

BEFORE SERVICING THE CHASSIS, READ THE SAFETY PRECAUTIONS IN THIS MANUAL.

CHASSIS : ML-012B

MODEL : RU-20LA61

website:http://biz.LGservice.com

e-mail:http://www.LGEservice.com/techsup.html

MONO DPM

STEREO

SAP

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SAFETY PRECAUTIONS

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 X-RADIATION, Shock, Fire, or other Hazards. Do not modify the original design without permission of manufacturer.

General Guidance

An lsolation 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 circuitary 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.

Due to high vacuum and large surface area of picture tube, extreme care should be used in handling the Picture Tube. Do not lift the Picture tube by it's Neck.

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 positioin, 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 1MΩ and 5.2MΩ. 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 1.5K/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 esposed 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 sepcified, 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

1.5 Kohm/10W

To Instrument's exposed METALLIC PARTS

Good Earth Ground such as WATER PIPE, CONDUIT etc.

AC Volt-meter

IMPORTANT SAFETY NOTICE

0.15uF

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SPECIFICATIONS.................................................................4

DESCRIPTION OF CONTROLS...........................................5

ADJUSTMENT INSTRUCTIONS ..........................................9

PRINTED CIRCUIT BOARD ...............................................10

BLOCK DIAGRAM...............................................................13

EXPLODED VIEW...............................................................14

EXPLODED VIEW PARTS LIST.........................................15

REPLACEMENT PARTS LIST............................................16

SCHEMATIC DIAGRAM..........................................................

TABLE OF CONTENTS

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SPECIFICATIONS

Model RU-15LA61 RU-20LA61

Horizontal size (Inches) 18.3 22.8 Height (Inches) 14.8 18.3 Thickness (Inches) 6.7 8 Weight (pounds) 13.9 21.6

Power requirements DC 12V/4.5A DC 15V/4.5A

Television system NTSC

Television channels VHF : 2 ~ 13, UHF : 14 ~ 69

Cable : 01 ~ 125

Television Screen LCD Panel

External antenna impedance 75 Ω

Power consumption 50 W 70 W

Audio output 3 W + 3 W 5 W + 5 W

Adapter (DC power) In : AC 100-240V ~ 1.5A-0.6A

50/60Hz, 115~180VA

Out : DC 12V, 5A

* CAUTION : For use only with Model No. SAD6012SE AC Adapter, manufactured by H &

E co., Ltd.

Power supply cordset : Standard North America three wire earth-grounding with

flexible cord SJT type or higher type.

* CAUTION : If replacement becomes necessary, replace with an exact duplicate.

Contact any LG authorized service center.

In: AC 100-240V ~ 1.6A-0.7A

50/60Hz

Out: DC 15V, 4.5A For use only with Model No.

SAD7015SE AC Adapter, manufactured by H & E co., Ltd.

In: AC 100-240V ~ 1.5A-0.6A

50/60Hz

Out: DC 12V, 5A For use only with Model No.

SAD6012SE AC Adapter, manufactured by H & E co., Ltd.

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DESCRIPTION OF CONTROLS

Front of the

Front of the TVTV

MONO DPM

STEREO

SAP

MONO DPM

SAP

STEREO

Remote Control Sensor

DPM Indicator

(RU-15LA61 Only)

SAP Indicator

Mono Indicator

Stereo Indicator

Power/Standby indicator

Illuminates red in standby mode, Illuminates green when the TV is turned on.

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DC IN (15V)

ANT IN

+75 Ω

COMPONENT(480i/480p/720p/1080i)

VIDEO IN

DVD/DTV IN

AUDIO

RLVIDEO

Y L R

AUDIO(MONO)

DC 12V

ANT IN

+75 Ω

PC INPUT

COMPONENT(480i/480p/720p/1080i)

SOUND

VIDEO IN

DVD/DTV IN

AUDIO

RLVIDEO

Y L R

AUDIO(MONO)

Back of the

Back of the TVTV

Audio/Video Input

- This manual mainly explains the features for the RU-15LA61

PC Input

PC sound Input

Antenna Input

DC 12V Input

DVD/DTV IN (Component (480i/480p/720p/1080i), AUDIO) Input

RU-15LA61

RU-20LA61

* Kensington

Security System Connector

DC 15V Input

DESCRIPTION OF CONTROLS

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MONO DPM

STEREO

SAP

Side of the

Side of the TVTV

S-VIDEO VIDEO

AUDIO

IN2

L / MONO

Side Control Panel

Side Connection Panel

Channel Buttons

Volume Buttons

vol

enter

on/off

video

/ I

Enter Button

Menu Button

TV·Video Button

On/Off Button

Headphone Jack S-Video Input

Video Input

Audio Input

DESCRIPTION OF CONTROLS

+ 14 hidden pages