AR-F12 (serv.man8). Maintenance, inspection and troubleshooting - Sharp Copying Equipment Service Manual (repair manual). Page 51

Checks

Are the connectors of the
paper pushing plate top
position sensor and the
saddle stitch controller PCB
connected correctly?

Is the wiring between the
sensor and the saddle
stitcher broken?

Is 5 VDC present at J9-13
on the saddle stitch
controller PCB?

Is J9-14 on the saddle stitch
controller PCB grounded
correctly?

Cause

Paper pushing plate
home position top
position sensor (PI15S;
disconnected)

Wiring

Power supply

Ground

Step

1

2

3

4

Yes/No

No

Yes

No

No

Action

Connect the
connectors.

Correct the wiring.

Replace the saddle
stitch controller PCB.

Checks

Check the switch actuator of
the inlet door. Do the switch
and the sensor operate
correctly?

Check the inlet door switch.
Is the switch normal?

Measure the voltage at J10-
8 on the saddle stitch
controller PCB with the inlet
cover open. Is it 5 V?

Measure the voltage
between J19-1 (+) and J19-2
(

−

) on the finisher controller

PCB. Is it 24 V?

Cause

Switch actuator

Inlet door switch
(MS1S)

Inlet cover sensor
(PI9S)

Power supply, wiring

Step

1

2

3

4

Yes/No

No

No

Yes

No

Yes

Action

Correct the
mechanism.

Replace the switch.

The sensor is faulty.
Replace the sensor.

Replace the finisher
controller PCB.

Check the wiring
between J19 on the
finisher controller
PCB and J1 on the
saddle stitch
controller PCB. If a
fault is found, correct
it. Otherwise, replace
the saddle stitch
controller PCB.