Star Micronics NX-1000 series - Power Supply Unit Abnormal

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TROUBLESHOOTING
4-2. Power Supply Circuit Abnormal
(1) Remove connector CN5 (CN6 for Commodore type) of the main logic board.
YES
Replace Fuse F1
Fuse is
blown again?
NO
START
Fuse F1
is blown?
NO
Fuse F2 or F3
is blown?
NO
Check operation.
END
Replace
1) Transformer
2) IC1
YES
F3 is for AC120 only
YES
YES
YES
NO
Replace
Fuse F2 or F3
Fuse is
blown again?
NO
ACS1
and ACS2 are
supplied?
NO
Replace
transformer
The no load voltages are below:
ACS2 AC29.9V
ACS1 AC8.5V
Check or replace
1) D1~D4
2) IC1
NO
Check or replace
1) DB1
2) TR1, TR3
+5V line
is supplied?
YES
+24V line
is supplied?
YES