LG CM9750 Service Manual page 45

ELECTRICAL TROUBLESHOOTING GUIDE
No -5 V
Is the
VCC -7 VA supplied to IC953
pin2?
YES
Is there
'H' signal at Q953
Base?
YES
Check or replace Q953, Q957.
Or check line of MAIN PCB is short or not.
No output AMP gate line
Is the VCC
14 VA supplied to IC952
pin1 to pin3?
YES
Check and replace IC952.
Or check line of MAIN PCB is short or not.
NO
Is the R965 normal?
Check or replace Q951.
NO
Check P_CTL
from μ-com.
NO
Is the R952 normal?
Check or replace D951, D952.
3-26
NO
YES
NO
YES
Check or replace R965, D959.
Check or replace R952.