LG CM9530 - Page 47

3-28
ELECTRICAL TROUBLESHOOTING GUIDE
No AMP output
Check PFC P.CTL from μ-com.
Check AMP P.CTL from μ-com.
Replace D908, Q955, PC903.
Replace D908, Q956, PC902.Replace F911.
Check or replace
IC904, Q907 ~ Q910.
Check or replace IC902
and check Q905, Q906 gate(Pin1)
components (Resistors, Diodes).
Q905, Q906 OK?
Replace Q905, Q906.
Check or replace D954, D955.
Check line of MAIN PCB is short or not.
Is the
C904 voltage
about 380 V?
F911 normal?
PFC P.CTL OK?
AMP P.CTL
OK?
Is the
VCC 12 V supplied to
IC904 Pin16?
Is the
VCC 12 V supplied to
IC902 Pin8?
NO
YES
NO
NO
NO
NO
YES
NO
YES
YES
YES
YES
NO
NO