Low-Voltage Power Supply - Oki C911 Maintenance Manual

Oki Data CONFIDENTIAL

2.3 Low-voltage Power Supply

2.3.1 Operation
Low-voltage power supply
Heater
circuit
Main power supply
Main power
AC
AC→24V
switch
Sub power supply
AC→5V
The low-voltage power supply has two kinds of power supply, which is main power supply (5V,
24V) and sub power supply (5VS0).
The main power supply (24V, 5V) is turned on and off by CE1 ASIC of the PU/CU board.
The sub-power supply (5VS0) is turned on when plugging the AC cable into the socket and
turning on the Main power switch.
Therefore, the maintenance operations should be performed after turning off the Main power
switch, unplugging the AC cable and checking the LED on the PU/CU board lighted off.
Turning ON and OFF of 5VS to the main CPU is performed by the Power supply control CPU.
45530603TH Rev.2
To the fuser unit
PU/CU board
24V
To the motor driver
5V
24V→5V
CE1
ASIC
5VS0 5VS
Power
supply
control CPU
Power switch
2.3.2 Power-supply Voltage in Each Mode
The output voltage value of the low-voltage power supply is different in each operation mode
as shown in the following table.
When measuring the output voltage value of the low-voltage power supply, the judgment of
validity should be performed based on the following table.
Output voltage value of the low-voltage power supply
Operation mode
24V line
In operation, and
24V
Standby
Power save 24V
Sleep OFF
OFF OFF
2.3.3 Thermistor for Temperature Alarm
The low-voltage power supply mounts the thermistor for temperature alarm.
When the temperature of the low-voltage power supply is abnormal, Service Call SC SC166-
01, 02, 03 is displayed.
For details and handling methods of each service call, refer to 'Service Call Error List' in the
section 4 Troubleshooting Procedure.
2. DESCRIPTION OF OPERATION
Power-supply
voltage value
in the PU/CU
board
5V line 5VS0 line 5VS line
5V 5V 5V
5V 5V 5V
OFF 5V 5V
OFF 5V OFF
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