Outline Of Power Supply Circuit Board - Epson Stylus Pro 7400 Service Manual

EPSON Stylus Pro 7400/7800/9400/9800

2.4 Outline of Power Supply Circuit Board

The 100 V AC power from the wall outlet is supplied via the power cable, an accessory
of Stylus Pro 7600/9600, into the Inlet of the printer and to the Power Supply Circuit
Board.
The power switch constitutes a secondary power switch system. The secondary power
switch system operates as follows: even with the power switch turned off, the Power
Supply Circuit Board is operating by a slight power as long as the power cable is
connected.
Even after the power switch is turned off, the Power Supply Circuit
C A U T I O N
Board does not stop operating immediately, but power is kept on
until the ink system ending sequence is complete.
Do not disconnect the power cable or do not shut off power by
turning off any power switch other than that on the printer.
The Power Supply Circuit Board is equipped with a fuse for overcurrent protection.
The rating of the fuse is:
Table 2-9. Fuse Rating
250 VAC/6.3 A
Operating Principles
Fuse Rating
Outline of Power Supply Circuit Board
There are three control signals between the C594 MAIN Board and the Power Supply
Circuit Board as shown in the table below.
Table 2-10. Explanation of Operation
Signal Name
REM_ON Operating Turned ON/OFF by C594 MAIN Board.
(MAIN →
• When these terminals are shorted, the drive system
Power Supply) power supplies 24 VDC and 42 VDC become inactive.
Off • When these terminals are open (= H), the drive system
power supplies 24 VDC and 42 VDC become 0 VDC.
• The 5 VDC power is not controlled with these
terminals.
AC_OFF Operating When each output from the Power Supply Circuit Board
←
(MAIN (= H) has become inactive because of turning off of the power
Power Supply) switch or when the input voltage has dropped below the
rated voltage value, "H" signal is sent to the C594 MAIN
Board.
Off The power switch is turned on and the Power Supply
(= L) Circuit Board Unit starts operating so that each output
becomes active.
"L" signal is sent to the C594 MAIN Board.
POW_ON/OFF Operating Connected to the power switch on the Panel Unit.
→
(Panel /MAIN • These terminals are shorted when the switch is ON.
Power Supply)
The Power Supply Circuit Board becomes active.
Not operating • These terminals are open when the switch is OFF. The
Power Supply Unit keeps operating for several seconds
and then turns off.
Revision B
Function
168