Power Supply - Kyocera Mita FS-6750 Service Manual

Operation theory
Engine controller system

Power supply

The power supply contains the AC and DC power and distribution circuitry on the
board. The high voltage generator is not included on this board but on the separate
high-voltage board.
AC input and rectifier—Either 120 V or 230 V AC power arriving at CN1 is fed to
the AC line filter circuit (L4, L5, C3, etc.) and rectified by diode array BD1 to DC
power. Transistor Q1 performs switching of the DC power output for downverting it
to the 24 V and 5 V DC voltage by means of transformer T1.
24V DC power line—The 24 V DC at the secondary output of T1 is rectified by D1
and C13/C18 and delivered to connectors CN5 for distribution. The 24 V DC power
is referred to as VDD or VDDCOM and is used by the following components in the
en-gine system:
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The 24 V DC power is forcibly interrupted for safety whenever the printer top cover
or the drum unit access door is opened. For details, see page 26,
5 V DC power line—The 5 V DC at the secondary output of T1 is rectified by D2 and
C14/15, etc., like as for the 24 V DC power line. It also delivered to CN3 and CN4.
The 5 V DC power is referred to as VCC and is comprehensively used by the main
control-ler, sensors, engine controller, etc.
Power protection circtuit—In case of short-circuiting in the 5 V or 24 V DC load side
, a protection circuit is provided to avoid damaging the circuit.
Fuser heater power control—On the AC primary side, the fuser heater is wired in
series across CN2. The heater is switched on and off as being controlled by TRIAC
TRC1. TRC1 turns on the heater when HEATCOM (pin 8) at CN3 is energized by
command from the engine controller.
FS-6750
Face-up/down stack solenoids
Clutches (registration, feed, manual-feed)
Eraser
Fans
High-voltage generator (board)
Main motor and laser polygon motor
Clutches, motors, solenoids within the option units
4-31
.
Safety interlock