Read LG 42LC7D (CHASSIS:LB73A) Service Manual online
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Check input connect J700 , J701
Can you see the normal waveform?
YES
J700 , J701
may have problem. Replace this Jack.
After checking the Power of this chip, you should
decide to replace this or not.
NO
Check DDC communication lines(IC705 IC706
Pin5,6)
NO
YES
YES
YES
YES
After checking the Power of this chip, you should
decide to replace this or not.
Check HDCP communication lines(IC704 Pin5,6)
NO
After checking the trace of TMDS lines and
power of MST3361, you should decide to replace
MST3361 or not.
Check the input of MST3361(IC703)
This signal is TMDS.
Can you see the normal waveform?
NO
After checking the Power of MST3361 you
should decide to replace MST3361 or not.
Check the output of MST3361(IC703 ).
Can you see the normal waveform?
NO
This board has big problem because Main
chip(HD2.4) have some troubles.
After checking thoroughly all path once again,
You should decide to replace HD2.4 or not.
Check the input and output of HD2.4(IC401).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
NO
HDMI doesn’t display
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