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TROUBLESHOOTING

TV/CATV doesn￿t display

Check TU500 Pin15(Video output),

Pin16(Sound output)

Can you see the normal signal?

YES

Check the output of TR(Q503).

Can you see the normal waveform?

YES

Check the output of Main IC(IC100). Especially you should check

The H,V sync and clock.

Can you see the normal waveform?

YES

This board has big problem because Main IC(IC100) have some troubles.

After checking thoroughly all path once again, You should decide to replace Main Board or not.

NO

NO

NO

 

 

Could you measure voltage of

 

NO

 

 

You should check power line

 

 

 

TU800 & IIC lines?

 

 

 

 

 

 

 

 

 

& IIC lines.

 

 

 

Are they all normal?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

YES

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You should replace TUNER.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You should decide to replace TR(Q503)

 

 

 

 

 

or not.

 

 

 

 

 

 

 

 

 

 

 

 

 

After checking the Power of Main

 

 

 

 

 

IC(IC100) you should decide to replace

 

 

 

 

 

Main IC or not.

 

 

 

Copyright © 2007 LG Electronics. Inc. All right reserved.

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LGE Internal Use Only

Only for training and service purposes

 

 

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LG Electronics 425010, 425030, 425020 service manual Troubleshooting, TV/CATV doesnt display