LG NS9550F Service Manual

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 Q911 ~ Q914 gate(Pin2)
components (Resistors, Diodes).
Q911 ~ Q914 OK?
Replace Q911 ~ Q914.
Check or replace D953 ~ D956.
Check line of MAIN PCB is short or not.
Is the
C904, C905 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

LG NS9550F Specifications

General

Brand	LG
Model	NS9550F
Category	Stereo System
Language	English