LG 42PC5D-UC / 42PC5DC-UC (CHASSIS:PA-73E) Service Manual ▷ View online
- 21 -
TROUBLESHOOTING GUIDE
Component doesn’t display
Check J5004,J5005.
Can you see the normal waveform?
Check the input of Component
switch(IC5001,IC5002).
Can you see the normal waveform?
Check the output of Component
switch(IC5001,IC5002).
Can you see the normal waveform?
Check the input of MST3361(IC7004
Pin41,44,46).
Can you see the normal waveform?
YES
YES
YES
NO
J5004,J5005 may have problem. Replace this Jack.
Check the output of MST3361(IC7004 ).
Can you see the normal waveform?
YES
Check the input and output of
BCM3550(IC4006). Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
YES
NO
After checking the input TR of component, you should
decide to replace component switch or not.
NO
NO
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
NO
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.
After checking the Power of component switch you
should decide to replace component switch or not.
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
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TROUBLESHOOTING GUIDE
RGB_PC doesn’t display
Check input connect P7004.
Can you see the normal waveform?
Check the input of Component switch(IC5002).
Can you see the normal waveform?
Check the output of Component switch(IC5002).
Can you see the normal waveform?
Check the input of MST3361(IC7004
Pin41,44,46).
Can you see the normal waveform?
YES
YES
YES
NO
P7004 may have problem. Replace this Jack.
Check the output of MST3361(IC7004 ).
Can you see the normal waveform?
YES
Check the input and output of
BCM3550(IC4006). Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
YES
NO
After checking the input TR of RGBHV, you should
decide to replace these components or not.
NO
NO
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
NO
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.
After checking the Power of RGB switch you should
decide to replace component switch or not.
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
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TROUBLESHOOTING GUIDE
HDMI doesn’t display
Check input connect P7007.
Can you see the normal waveform?
Check DDC communication lines(IC7013 Pin5,6)
Check the input of MST3361(IC7004)
This signal is TMDS.
Can you see the normal waveform?
YES
YES
NO
P7007 may have problem. Replace this Jack.
Check the output of MST3361(IC7004 ).
Can you see the normal waveform?
YES
Check the input and output of
BCM3550(IC4006). Especially you should check
The H,V sync and clock.
Can you see the normal waveform?
YES
YES
NO
NO
After checking the trace of TMDS lines and power of
MST3361, you should decide to replace MST3361 or not.
NO
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.
After checking the Power of this chip, you should
decide to replace this or not.
After checking the Power of MST3361 you should
decide to replace MST3361 or not.
YES
Check HDCP communication lines(IC7005 Pin5,6)
NO
After checking the Power of this chip, you should
decide to replace this or not.
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PRINTED CIRCUIT BOARDS
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