Star Micronics NX-1020 Technical Manual page 32

THEORY OF OPERATION
The utilization of voltage applied to the paper feed motor is described as follows.
Voltage to the paper feed motor is changed by setting CPU port P31 to LOW or HIGH and by turning transistors TR4 and
TR5 ON or OFF.
When TR5 is turned on, +25V is applied to the paper feed motor.
When TR5 is turned off, +5V is supplied to the motor via diode D2.
Fig. 2-13 Paper Feed Motor Driving Signals
Mode
Operation
Standby:
Voltage Application
+25VDC Motor Drive
+5VDC Holding Bias
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