Panasonic KX-FHD332C Service Manual page 169

When an original document is inserted and the start button pressed, pin 21 of IC501 goes to a
high level and the transistor Q507 turns on.This applies voltage to the LED array to light it. The
contact image sensor is driven by each of the FTG-F1 signals output from IC501, and the
original image illuminated by the LED array undergoes photoelectric conversion to output an
analog image signal (SIG). The analog image signal is input to the system ASIC on AIN1 (pin 3 of
IC501) and converted into 8-bit data by the A/D converter inside IC501. Then this signal
undergoes digital processing in order to obtain a high-quality image.
7.4.5. 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 Q507, Q504 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 IC510 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
document paper.
The timing chart is below.
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