COPYRIGHT © 1999 CANON INC. CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)III. POWER SUPPLYA. Power SupplyThe low-voltage power supply circuit in the power supply generates +24 VB and +5 VDC 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 theheat discharge fan 2.+24 VB, further, is also sent through each cover switch and is turned into +24 VARsupplied to the developing rotary motor PCB and +24 UH (Note) supplied to each PCBby 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 andsolenoids, 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 controllerPCB 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 P5SAVEis also used by the sensors.+5 V is also used to generate the +5 R signal to supply the printer board with 5 Vpower.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.CHAPTER 7 EXTERNALS/AUXILIARY MECHANISMS7-4Note:+24 UH is 24 V sent through the right cover switch and the delivery cover/front coverswitch and then through the FET switch; the 24 V power supplied to the heat dischargefan 3 and the pre-exposure LED without being lead through the FET switch is alsocalled +24 UH.Download free service manual at http://printer1.blogspot.com
