NAD M56, Service Manual

Page: 44 / 101

POWER on
Main Board
Timer Board
Check SMPS
"
PLEASE WAIT"
Display on VFD
OK?
CN901,
Pin6; +5.3V, Pin21; -30V,
Pin7; -27V, Pin11;
-24V?
NO
NO
YES
YES
YES
X901 Change
X901 10MHz
OK?
NO
YES
IC901 Change
R916
About 625kHz serial
Clock OK?
NO
YES
IC902 Change
R923
about 500kHz
OK?
NO
YES
DIG901 change
Check SMPS
“READING”
Display on VFD
OK?
CN701,
Pin5; 12V, Pin7; 5V,
Pin2; 3.3V, Pin11;
5V?
YES
IC701, IC702 Change,
IC703 Change,
IC705 Change,
IC706 Change,
IC704 Change.
CA726; 5V
CA723; 1.2V
CA725; 1.8V
NO
NO
YES
X504 Change
X504
54.000MHz
OK?
NO
YES
Check IC201 System part OK
3. SYSTEM PART
ELECTRICAL TROUBLESHOOTING GUIDE
3-30