Ricoh A318 Service Manual page 10

1 May 1993
6.2 A111 COPIER
115Vac
AC Drive
Board
(PCB2)
220/230/240Vac
The DF uses three dc power levels: +24 volts, +12 volts, and +5 volts.
When the main switch is turned on, the main transformer receives the wall
outlet ac power through the ac drive board and outputs 10 volts ac and 31
volts ac to the main dc power supply board. The main dc power supply board
then converts the 10 volts ac input to +5 volts dc and the 31 volts ac input to
+24 volts. Then, those two dc voltages are supplied to the DF main board
through the copier main board.
The regulator IC on the DF main board further steps down the 24 volts to +12
volts.
Main
Main DC
31Vac
Transformer
Power
(TR1)
Supply
Board
(PCB3)
10Vac
9
POWER DISTRIBUTION
+24V (VA)
+24V (VA)
Copier
Main
Board
(PCB1)
+5V (VC)
+5V (VC)
+24V +12V
Regulator
IC
5V
DF Main Board
(PCB1)