LG Electronics 425030, 425010, 425020 service manual AV1/2/3 doesnt display

Check J600,J600,JK607,JK618

Can you see the normal

waveform?

YES

NO

J600,J601 or SIDE AV may have problem. Replace this Jack or SIDE AV.

Check the input of Video

switch(IC700).

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

After checking the Power of AV switch you should decide to replace AV switch or not.

After checking the Power of Main

IC(IC100) you should decide to replace

Main IC or not.