Canon LBP-860 Service Manual page 91

A.
Outline
The AC line voltage is supplied to the low-voltage power supply circuit in the power supply by
turning the power switch (SWIOl) ON.
The low-voltage power supply circuit generates +24 VDC and +5 VDC. The +24 VDC is
supplied to the main motor. scanner motor, and exhaust fan to drive them, and to the high-
voltage power supply I'CB. The +5 VDC is supplied to the sensors and Es on the DC controller
The +24 VDC consists of two types of voltage: +24VA, which is normally supplied from the
power supply, and +24VB, which is cut when the upper cover is opened and the door switch
The block diagram is shown below.
i
To fixing roller heater
B. Protective System
II' a short circuit or other fault causes excessive current from the +24 VDC and +5 VDC power
supplies, the overcurrent protection system automatically shuts off the output voltage to
protect the power supply. To reset the power supply after such a shutdown, switch the power
OFF, correct the fault, then switch the power back ON again. If overcurrent flows through the
AC line. the circuit breaker in the power supply trips and the output voltage is shut off.
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Power supply
CHAPTER 2