Other Controls - Canon LBP-1760 Service Manual

CHAPTER 2
F. Other Controls
1. Main motor control
Figure 2-2-11 shows the main motor control circuit.
Engine controller PCB
CPU
IC501
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
+24VA
J52-3
+3.3V
J52-4
J52-2
92 /MRDY
+3.3V
J52-1
43
J52-5
73 MON
J52-6
J52-7
Figure 2-2-11
Main motor
J301-5
M101
J301-4
/MRDY
J301-6
/HALF
J301-7
M
/MON
J301-3
J301-2
J301-1