Panasonic KX-FC379CX Service Manual page 166

8.4.6. Stepping Motor Drive Circuit (TX)
1. Function
The stepping motor works for transmission.
2. Motor
During motor driving, pin 131 of ASIC IC501 becomes a high level, and Q504, Q508 turns ON. As a result, +24V is supplied
to the motor coil.
Stepping pulses are output from ASIC IC501 pins, 125, 128~130, causing driver IC509 pins, 10~13 to drive the Motor Coil. The
motor coil is energized sequentially in 2 phase increments, which causes a 1-step rotation. A 1-step rotation feeds 0.13 mm of
document paper.
The timing chart is below.
When the motor suspends while it is in the receive mode (about 70~80 msec), pin 131 of ASIC IC501 becomes a low level and
Q504 turns OFF. Then Q508 also turns OFF, and instead of +24 V, +5 V is supplied through D504 so that the motor is held in
place. When the system is in the stand-by mode, all of the motor drive transistors turn OFF. Consequently, the motor current
stops.
Stepping Motor Drive Mode
Function Mode
Copy Fine or Photo
Super Fine
Paper Feed ———
Stand-by ———
165
KX-FC379CX
Phase Pattern Speed
1-2 432 pps (t=1/432)
1-2 216 pps (t=1/216)
1-2 432 pps (t=1/432)
All phases are None
currently off.