Motor Drive Section - Panasonic KX-MB771GR Service Manual

KX-MB771GR
6.7.

MOTOR DRIVE SECTION

6.7.1. Engine Motor Control Circuit
1. Functions
All driving forces of printer engine part are supplied by this engine motor.
Engine motor is controlled so as to rotate at constant speed during printing and copying.
2. Motor operation
<Start operation>
In order to start the motor rotation, following 3 signals are supplied from IC300.
1. SS signal (Output pin: Pin B12/Output Signal: "H")
When this signal is inverted by transistor Q502 and becomes "L", motor recognize this signal as "start" signal.
2. Clock signal (Output pin: Pin A12/Output Signal: Pulse)
Pulse frequency :approx. 1.9KHz (at normal printing speed, )
Pulse frequency :approx. 0.5KHz.(at half printing speed)
This signal is also inverted by transistor Q525, and supplied to motor as "clock" signal .
3. Brake signal (Output pin: Pin C12/Output Signal: "H")
When this signal is inverted by transistor Q526 and becomes "L", motor recognize this signal as "brake off" signal.
When motor reaches constant speed, "L" signal is supplied from motor to IC300 pin B12 as "Lock detect (LD)" signal.
if "LD" signal does not becomes "L" within predetermined period after "SS" signal becomes "H", or if "LD" signal becomes
"H" during rotation, it is judged that motor Error occurred.
Timing Chart of Start operation
30