Engine I/O; Engine Pcb - Brother HL 1240 - B/W Laser Printer Service Manual

CHAPTER 3 THEORY OF OPERATION
1.3.8

Engine I/O

HL-1240
Fig. 3-17 shows the engine interface circuit. The interface with the engine PCB is by full-
duplex synchronous serial method.
HL-1250
Fig. 3-18 shows the engine interface circuit. The interface with the engine PCB is by full-
duplex synchronous serial method.
1.4

Engine PCB

The gate array which transforms the serial signal from the main PCB into the parallel signal is
mounted on the engine PCB.
The engine PCB controls the following parts by using the transferred signal data;
Main motor


Panel PCB


Fan motor


Thermistor


Polygon motor


Solenoid


High-voltage power supply


Fig. 3-17
Fig. 3-18
Toner sensor


Cover sensor


Front registration sensor


Rear registration sensor


Upper paper cassette sensor (HL-1250 only)


Lower paper cassette registration sensor (HL-1250 only)


3-14