Hdmi Doesn't Display - LG 20LS7DC Service Manual

5. HDMI doesn't display

Check input connect J7101.
Can you see the normal waveform?
Check DDC communication lines(IC702 Pin5,6)
Check HDCP communication lines(IC701 Pin5,6)
Check the input of MST3382M(IC7012).
This signal is TMDS.
Can you see the normal waveform?
Check the output of MST3361(IC7012)
Can you see the normal waveform?.
Check the input and output of BCM3550(IC1001).
Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
Yes
J7101 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 MST3382M, you should decide to replace
MST3382M or not.
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
This board has big problem because
Main chip(BCM3550) have some troubles.
After checking thoroughly all path once again,
You should decide to replace BCM3550 or not.
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