Power Supply Circuit - Epson Perfection 4870 Photo Service Manual

Perfection 4870 Photo

2.3 Power Supply Circuit

This Power Supply Circuit Board generates DC power necessary to drive the Control
Board and Scanner Engine. Table 2-1
destination basis.
Table 2-1. Destination-based Power Supply Circuit Boards
Specifications Unit Part No.
100-120VAC region 2027705
220-240VAC region 2027704
The output of the Power Supply Circuit Board is provided by closing/opening the No. 4
pin of the CN102 Connector. When the pin is open, the output voltages indicated in
Table 2-2 become active. The output voltages have their respective overcurrent
protection and overvoltage protection circuit functions.
Table 2-2. Power Supply Circuit Board Outputs and Protective Functions
Overcurrent Protection
Output Output
(Protective circuit
Voltage Current
operation current value)
Voltage droop with
current decrease.
5 VDC 1.2 A
Automatic recovery.
(1A or less)
Depending on the
drooping characteristic of
12 VDC 0.2 A
the regulator. Automatic
recovery. (0.5A or less)
Shutdown. Switch power
off, then on again to
24 VDC 0.7 A
recover.
NOTE 1: If any of the outputs shuts down, all the other outputs also shut down.
2: The input OFF time necessary for recovery is 5 minutes (maximum).
OPERATING PRINCIPLES
indicates the Power Supply Circuit Boards on a
Fuse Rating
2.5 A/125 VAC
T2.5AH/250 VAC
Overvoltage Protection
(Protective circuit
operation voltage value)
Shutdown. Switch
power off, then on again
to recover. (5.5 to
7.5VDC)
Shutdown. Switch
power off, then on again
to recover. (14 to
17VDC)
Shutdown. Switch
power off, then on again
to recover. (28 to
33VDC)
Power Supply Circuit
Revision A
26