User manual

95.08.23.11.31
Color LaserWriter 12/600 PS Basics & Theory 1–144
When the front door, the fuser access cover, and the pickup cover are
closed, the door switch (SW2) is automatically turned on and the power
supply is sent to the driving loads.
This circuit also supplies +24 VDC and +5 VDC, which are required
for the printer itself. The +24 VDC is supplied for the motors, the
exhaust fans, the clutches and other driving components, as well as for
the cassette pickup board and the high-voltage power supply board.
The 12V power is generated in the DC controller to drive the laser
diode.
The +24 VDC consists of
• Normal +24 VA, which is shut off when SW2 is turned off by the
opening of the front door, fuser access cover, or the pickup cover.
• Voltage of +24 VB, which is always on whether SW2 is turned on or
off.
• Voltage of +24 VC, which is shut off in the power-saving mode (see
below) or when the cover is opened, is generated in the mechanical
controller board.
The 5 V power supplied to the I/O controller is monitored using the 5
VB signal to ensure it is always supplied.
The printer enters the energy-saving mode on command from the I/O
controller. It returns to the normal mode when a command to cancel the
power-saving mode is received from the I/O controller.