Panasonic KX-FHD332C Service Manual page 171

becomes a low level and Q507 turns OFF. Then Q504 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.
7.4.6. 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, 16~13 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.
Stepping Motor Drive Mode
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