No PVDD
YES
F901 normal?
Replace F901 (Use the same fuse).
YES
NO
BD901 normal?
Replace BD901.
YES
NO
TH901(TH903) normal?
Replace TH901.
YES
YES
NO
Is Vcc
(10 V ~ 18 V) supplied to
IC911 Pin4?
D903 normal?
YES
NO
Check or replace D903.
• Check P-CTRL "H" signal from MCS.
• Check PC902.
Q901 normal?
Replace Q901.
Check or replace Q911.
YES
NO
D951 normal?
Replace D951.
YES
NO
Is there about 2.5 V
at IC951 Pin1?
Replace IC951.
YES
NO
Q911 base "H"?
Power line of main PCB is short.
NO
NO
3-18
AUDIO ELECTRICAL TROUBLESHOOTIHG GUIDE
Summary of Contents for CM4550
Page 13: ...2 2 ...
Page 17: ...A60 4 SPEAKER SECTION 4 1 FRONT SPEAKER CMS4550F ...
Page 18: ...2 9 A90 4 2 SUBWOOFER SPEAKER CMS4550W ...
Page 19: ...2 10 ...
Page 50: ...4 USB 13 USB_5 V D D 14 3 31 IC501 PIN A8 IC501 PIN A7 ...
Page 51: ...3 32 ...
Page 66: ...3 61 3 62 2 MAIN P C BOARD TOP VIEW BOTTOM VIEW ...
Page 67: ...3 63 3 64 3 FRONT P C BOARD TOP VIEW BOTTOM VIEW ...