Power Supply Unit - Toshiba 8070 Service Manual

17. POWER SUPPLY UNIT

17.1 Configuration
The power supply unit comprises an AC filter and isolated DC output circuit.
(1) AC filter
This filter removes external electrical noise, and prevents leakage of electrical noise generated within
the machine to the outside.
(2) DC output circuit
DC output is divided into the following two lines:
Main line
1
Door switch line: This power supply passes via the door switch and is used by the entire ma-
2
17.2 Operation of DC Output Circuit
(1) Start
When the main switch on the main unit is turned ON, the power on all lines starts up if the door is
closed.
(2) Stop
When the main switch on the main unit is turned OFF, the power OFF signal (PWR-DN) signal is
output after the momentary power failure guarantee time (20 ms or more) passes. The power voltage
is dropped after the rated voltage is held for the minimum hold time (10 ms or more) after the power
OFF signal is output.
(3) Output protection
Each of the output lines has a built-in overcurrent protection circuit (fuse, internal protection circuit)
and overvoltage protection. This prevents trouble such as damage to the secondary circuit or errone-
ous operation caused by overcurrent (e.g. shorting of the load) or overvoltage (e.g. shorting between
different voltages) from occurring.
When the protection circuit has operated, remove the cause of circuit operation (e.g. short), and
reset the circuit by turning the power OFF then ON again.
Mar. 1999 © TOSHIBA TEC
: This power supply is used by the entire machine during image formation. 4
voltages (+3.35V, +5.1V, +12V, +24V) are output when the machine is started
up by turning the power switch ON.
chine during image formation. 3 voltages (+5.1V, +24V, +36V) are output when
the machine is started up by turning the power switch ON and operation of the
door switches (2 locations).
17 - 1 6570/5570 POWER SUPPPLY