Panasonic KX-FC379CX Service Manual page 165

KX-FC379CX
8.4.5. Stepping Motor Drive Circuit (RX)
1. Function
The stepping motor works for reception.
2. Motor
During motor driving, pin 124 of ASIC IC501 becomes a high level, and Q503, Q502 turns ON. As a result, +24V is supplied
to the motor coil.
Stepping pulses are output from ASIC IC501 pins, 120~123, causing driver IC508 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
recording paper.
The timing chart is below.
When the motor suspends while it is in the receive mode (about 70~80 msec), pin 124 of ASIC IC501 becomes a low level and
Q503 turns OFF. Then Q502 also turns OFF, and instead of +24 V, +5 V is supplied through D501 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 ———
164
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.