Power Supply; Iii. Power Supply - Canon CP660 Service Manual

CHAPTER 7 EXTERNALS/AUXILIARY MECHANISMS

III. POWER SUPPLY

A.

Power Supply

The low-voltage power supply circuit in the power supply generates +24 VB and +5 V
DC power needed by the printer unit.
+24 VB is used as it is as the source of power by the heat discharge fan 1 and the
heat discharge fan 2.
+24 VB, further, is also sent through each cover switch and is turned into +24 VAR
supplied to the developing rotary motor PCB and +24 UH (Note) supplied to each PCB
by way of the FET switch on the main relay PCB.
+24 VAR is used as the source of power by the color developing rotary motor and
solenoids, while +24 UH is used by loads and PCBs.
+5 V is supplied to the DC controller PCB as its source of power. The DC controller
PCB uses +5 V to generate the PSAVE* and P5SAVE signal, causing PSAVE* to go '0'
in response to a power save command, thereby turning off the FET switch and, ultimate-
ly, cutting +24 UH. At this time, the sensors will also be deprived of power, since P5SAVE
is also used by the sensors.
+5 V is also used to generate the +5 R signal to supply the printer board with 5 V
power.
The low-voltage power supply circuit monitors the 5 VS signal fed back by the DC con-
troller PCB to ensure that 5 V supplied to the printer board remains at a correct level.
Note:
+24 UH is 24 V sent through the right cover switch and the delivery cover/front cover
switch and then through the FET switch; the 24 V power supplied to the heat discharge
fan 3 and the pre-exposure LED without being lead through the FET switch is also
called +24 UH.
7-4
COPYRIGHT © 1999 CANON INC.
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CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)