LG Electronics 425030, 425010, 425020 service manual Hdmi doesnt display

Check input connect J900 , J901,

J902

Can you see the normal

waveform?

YES

Check DDC communication

lines(IC900, IC901, IC903 Pin5,6)

YES

Check HDCP communication

lines(IC902)

YES

Check the input of HDMI

Seitch(IC902)

This signal is TMDS.

Can you see the normal waveform?

YES

Check the output of HDMI

Switch(IC902).

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

NO

NO

NO

J900 , J901, J902

may have problem. Replace this Jack.

After checking the Power of this chip, you should decide to replace this or not.

After checking the Power of this chip, you should decide to replace this or not.

After checking the trace of TMDS lines and power of HDMI Switch, you should decide to replace HDMI Switch or not.

After checking the Power of HDMI Switch you should decide to replace MST3361 or not.

After checking the Power of Main

IC(IC100) you should decide to replace

Main IC or not.