Canon LBP1760P, Service Manual

Page: 58 / 394

F. Other Controls
1. Main motor control
Figure 2-2-11 shows the main motor control circuit.
Figure 2-2-11
The main motor is a DC brushless motor with hall elements, and is unified with the motor drive
circuit.
The CPU (IC501) sets the MAIN MOTOR DRIVE signal (/MON) to “L” and rotates the main
motor. When printing at 1200DPI, the CPU sets the MAIN MOTOR ROTATION SWITCHING sig-
nal (/HALF) to “L” and decreases the rotation speed of the main motor to half.
When the main motor rotates and reaches its prescribed speed, it sets the MAIN MOTOR
READY signal (/MRDY) to “L.”
The CPU notifies the video controller of a main motor failure in the following cases:
1) The /MRDY signal does not become “L” after 700ms from the main motor rotation start.
2) The /MRDY signal becomes “L” once, but goes “H” for more than 0.1 second continuously
during normal rotation.
2 - 20
CHAPTER 2
Engine controller PCB
CPU
J301-1
Main motor
J301-7
J52-7
J52-1
73 MON
J52-5 J301-3
J52-6 J301-2
M
J301-6 J52-2
J301-4
J52-4
J301-5 J52-3
/HALF
M101
/MRDY
/MON
+3.3V
43
92 /MRDY
+3.3V
IC501
+24VA