Power Circuit; Power Circuit Protection - Canon BJ-W3000 Service Manual

CHAPTER 2. BASIC OPERATION
B. Power Circuit
1. AC power supply
By plugging in the power cord and turning
the power switch (SW1) ON, AC power is
supplied to the DC power supply PCB.
2. DC power supply
When the power cord is plugged in and
the power switch (SW1) is turned ON, the
DC power supply rectifies the supplied AC
power, decreases the voltage, and smoothes
and supplies +26.5V±5% and +5.1V±5% DC
power.
The carriage controller decreases the
voltage of the power supplied from the DC
power supply from +26V to +24V and sup-
plies power to the BJ cartridge.
DC power of +24V for driving the head
(VH), +5V (HV5) for the HEAT signal, and
+5V (R5V) for the rank signal are supplied to
the BJ cartridge. The output is controlled by
the engine controller.
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C. Power Circuit Protection
On the DC power supply, fuse F1 is
provided on the primary side as a safety
measure. On the secondary side, overcurrent
protection and overvoltage protection circuits
are provided.
If an overcurrent or overvoltage condition
occurs due to a short circuit in the power
line, etc., a protection circuit will actuate to
stop all the outputs from the DC power
supply.
By turning OFF the power switch, waiting
for more than 1 minute, and then turning the
power switch ON again, the protection
circuit is reset and the output is recovered.
CAUTION
• Before recovering the output, be
sure to remove the cause of the prob-
lem in the protective circuit.
• If the load is short-circuited often,
or short circuit and recovery are
repeated, the fuse incorporated in the
DC power supply may blow.