AR-FN2 (serv.man10). ARFN2 Service Manual-Circuit Descriptions - Sharp Copying Equipment Service Manual (repair manual). Page 12

This circuit controls rotation, stop, and rotating direction of DTM and the motor current. It is composed of the G/A (IC5), the constant-current
chopper system driver IC (IC11), etc. 
The G/A (IC5-78 

~

 81 pin) outputs the stepping motor drive excitement pattern signal to control the motor rotating speed and the rotating direction.

The PWM signal outputted from the G/A (IC 5-51 pin) is divided and integrated with R89, R15, and C62 to be converted into a constant voltage. The
converted voltage is inputted to IC11-9 pin and 11 pin to set the motor current value. The motor current value is controlled arbitrarily by varying the
ON DUTY of the PWM signal. 
C89- 92 and C101 are for absorbing noises. C59 and C62 are for reducing sounds when the motor is held. C50 and C69 are for stabilizing the +5V
power. C66 is for stabilizing the ST +24V power. 

This circuit controls rotation, stop, and rotating direction of DSM and the motor current. It is composed of the G/A (IC5), the constant-current
chopper system driver IC (IC7), etc. 
The G/A (IC5-25 

~

 28 pin) outputs the stepping motor drive excitement pattern signal to control the motor rotating speed and the rotating direction.

The PWM signal outputted from the G/A (IC 5-35 pin) is divided and integrated with R93, R94 and C64 to be converted into a constant voltage. The
converted voltage is inputted to IC7-9 pin and 11 pin to set the motor current value. The motor current value is controlled arbitrarily by varying the
ON DUTY of the PWM signal. 
C93- 96 and C103 are for absorbing noises. C61 and C64 are for reducing sounds when the motor is held. C47 and C68 are for stabilizing the +5V
power. C65 is for stabilizing the ST +24V power. 

Paper transport motor drive circuit

paper transport motor
(DTM)

Document alignment
motor  (DSM)

Document alignment motor

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