Ricoh IM 550F Field Service Manual page 231

4.Replacement and Adjustment
4. Replacement and Adjustment
Notes on the Main Power Switch
The main power button of this machine has been changed to a push-button switch (push button) from
the conventional rocker switch. The push switch has characteristics and specifications different from the
rocker switch. Care must be taken when replacing and adjusting parts.
Characteristics of the Push Switch (DC Switch)
Power is supplied to the machine even the main power is turned OFF.
The push switch in this machine uses DC (direct current). Therefore, if the AC power cord is connected
to an electrical outlet, power is supplied to the controller board (PCB15), the operation unit, and other
modules even when the main power is turned OFF. When replacing the controller board (PCB15) and
the operation unit in this state, not only these boards, it will damage other electrical components. So,
when performing maintenance work such as replacing parts, in addition to turning off the main power
with the push switch, always unplug the AC power cord.
When you disconnect the power cord from the AC wall outlet, inside the machine there is
still residual charge.
When you disconnect the power cord from the AC wall outlet, inside the machine for a while there is still
residual charge. Therefore, if you remove boards in this state, it can blow a fuse or cause memory
failure.
--How to discharge the residual charge inside the machine--
After you unplug the power cord from the AC wall outlet, be sure to press the main power switch in
order to discharge the residual charge from inside the machine. Thus, the charge remaining in the
machine is released, and it is possible to remove boards.
When you reconnect the AC power cord into an AC wall outlet, the machine will start
automatically.
In order to remove the residual charge, push the main power switch while you disconnect the AC power
cord. At that time, the power ON flag inside the machine is set. Therefore, after you finish work on the
machine and reconnect the power cord to the AC, even if you do not press the main power switch, the
machine will start automatically and the moving parts will begin to move. When working on moving
parts, be careful that fingers or clothes do not get caught.
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Automatic restart deals with cases when you accidentally unplugged the AC power cord or
unexpected power outages. By keeping the power flag ON, after the resumption of power, the
machine will start up automatically.
In rare cases, when you reconnect the AC power cord to a power outlet, the machine does not start
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