Panasonic KX-FT72BR-G Service Manual page 113

5.4.5. STEPPING MOTOR DRIVE CIRCUIT
1. Function
One individual stepping motor is used for transmission and reception. It feeds the document or recording paper synchronized
for reading or printing.
2. Circuit Operation
During motor drive, gate array IC1 pin 153 becomes a high level, and Q14 and Q7 go ON as a result. +24 V is supplied to the
motor coil.
Stepping pulses are output from gate array IC1, causing driver IC7 to go ON. The motor coil is energized sequentially in 2 phase
increments or 1-2 phase increments, which causes a 1-step rotation. A 1-step rotation is 0.13mm of recording paper or
document paper. The timing chart is below.
Copy
FAX
When the motor is OFF, gate array IC1 pin 153 becomes a low level and Q14 and Q7 also turns OFF. Instead of +24V, +5V is
supplied through D2 so that the motor is held in place.
Stepping Motor Phase Pattern
Function Mode
Fine/Half Tone
Super Fine
STD
Fine/Half Tone
Super Fine
——— Paper Feed
Phase Pattern
1-2 217 pps
1-2 108.5 pps
2 217 pps
1-2 217 pps
1-2 108.5 pps
2-2 434 pps
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Speed
KX-FT72BR-G