AR-CF1 (serv.man3). Finisher unit basic operation - Sharp Copying Equipment Service Manual (repair manual). Page 57

The finisher controller PCB is supplied with 24 VDC power (and 5 VDC power) when the host

machine is turned on. 24 VDC one is used to drive the motor solenoids, while 5 VDC is used for
sensors and ICs on PCBs. Both lines are also used to feed power from the finisher controller PCB to
the saddle stitch controller PCB. Power is also supplied to the punch driver PCB when the optional
puncher unit is mounted.

Some of the 24 VDC power used to drive motors is cut off when the door switch (MS1) is open.

The power to the saddle stitch controller PCB, however, will not be cut off.

Figure 2-301 is a block diagram showing the power supply system.

J1-1

J2-6

Saddle stitch 
controller PCB 
(Saddle Finisher) 

Door switch

Circuit breaker

Motor

Motor

Solenoid

Host 

machine

Finisher controller PCB

Sensors

Logic

Punch driver PCB
(Puncher Unit (option))

(CB1)

(MS1)

The 24 VDC power line used to drive motors and solenoids is equipped with a circuit breaker

(CB1) for protection against overcurrent. The 24 V line used to drive the first feed motor (M1),
alignment motor (M3), and stapler shift motor (M4) are equipped with a fuse, which is designed to
blow when an overcurrent occurs.