Brother FAX-170 Service Manual page 29

5 Transistor array which consists of seven transistors
5-1: Transistors that control the rotation direction of the motor according to the MM4
through MM1 signals.
5-2: Transistor that turns on and off the solenoid.
The combination of the solenoid state and the motor rotation direction deter-
mines to which the motor torque should be transmitted, the cutter, the document
feeding mechanism, or the paper feeding mechanism.
5-3: Transistor that turns on and off the CR1 relay for switching on and off the +26V
power source to the thermal recording head.
5-4: Transistor that turns on and off the CML relay.
6 Document front and rear sensor circuitry that is active only while the SEON signal is on.
The LEDs for the sensors are driven by the +26V source.
6-1: PH2, document rear sensor
6-2: PH1, document front sensor
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