Sharp AR-650 Service Handbook page 152

[CBC] Saddle stitcher alignment motor is abnormal
Is the alignment plate home position sensor (PI5S) normal?
No
Yes
Is the alignment motor (M5S) operating at the specified timing?
Yes
No
Is the alignment plate drive mechanism normal?
No
Yes
Does replacement of the alignment motor (M5S) rectify the trouble?
No
Yes
END
[CBD] Saddle stitcher guide motor is abnormal
Is the guide plate home position sensor (PI13S) normal?
No
Yes
Is the guide motor (M3S) operating at the fixed timing?
Yes
No
Is the guide plate drive mechanism normal?
No
Yes
Does replacement of the guide motor (M3S) rectify the trouble?
No
Yes
END
TROUBLE SHOOTING
Replace the sensor.
Replace the saddle stitcher controller board.
Correct the mechanism.
Replace the saddle stitcher controller board.
Replace the sensor.
Replace the saddle stitcher controller board.
Correct the mechanism.
Replace the saddle stitcher controller board.
4 - 24