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3. OPERATIONS AND TIMING
V. POWER SUPPLY
A.
AC Driver/DC Power Supply,
1.
Outline
The AC driver/DC
power supply PCB is
supplied
with
AC power
when
the door
switch (SW2) and the power switch (SWl)
go.ON.
On the other
hand,
the
DC power
supply supplies the main body with 24 VDC
and 5 VDC.
24 VDC is used to drive the scanner
motor (M2), fans and solenoids
as well as
high-voltage
transformer
(HVT); 5 VDC is
used by the sensors
and ICs on the DC
controller PCB.
2.
DC Power Supply
Circuit
The 24 VDC for the DC power supply is
supplied by the switching regulator.
The
5 VDC,
on the other
hand,
is
supplied
by the DC/DC
converter
after
conversion
from 24 VDC.
The DC/DC
converter
generates
the
reset signal
(RESET)
after power-on
and
until the 5VDC supply stabilizes to reset the
micro
processor,
thereby
preventing
malfunction
of the micro processor.
3.
AC Driver Circuit
'-
The DC power
supply/AC
driver
PCB
has an AC driver circuit and, based on the
signals from the DC controller PCB, controls
the SSRs
and relays
on the DC power
supply/AC
driver PCB to drive AC loads.
If the DC controller
PCB detects
an
error, the ACOFF signal is generated
to turn
the
relay
(KIOI)
on
the
DC
power
supply/AC
driver PCB OFF, thereby shutting
off the power to the lamp regulator and the
fixing heater.
When the power is shut off, switch the
copier OFF, and identify
the cause;
then,
switch the copier OFF.
Note that repeated
short-circuiting
and
resetting can cause the built-in fuse to blow.
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