Outline Of Power Supply Circuit Board; Operational Descriptions - Epson Stylus Pro 4400 Service Manual

EPSON Stylus Pro 4400/4450/4800/4880/4880C

2.4 Outline of Power Supply Circuit Board

100VAC from electric outlet is supplied to Power Supply Circuit Board through
a Power Cable and AC Inlet.
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
C A U T I O N
Circuit Board does not stop operating immediately, but
power is kept on until the ink system ending sequence is
completed.
Do not disconnect the Power Cable or do not shut off power
by turning off any power switch other than that on the
printer.
Operating Principles
There are three control signals between the BOARD ASSY., MAIN and the
Power Supply Circuit Board. Table below describes details of the control
signals:
Signal Name
REM_ON
(MAIN → Power
Supply)
AC_OFF
(MAIN ← Power
Supply)
POWER_SW
(Panel/MAIN →
Power Supply)
Outline of Power Supply Circuit Board
Table 2-15. Operational Descriptions
Function
Operating Turned ON/OFF by BOARD ASSY., MAIN.
• When these terminals are shorted, the drive
system power supplies 28 VDC and 42 VDC
are active.
OFF • When these terminals are open (= L), the
drive system power supplies 28 VDC and 42
VDC are 0 VDC.
• The 5 VDC power is not controlled with these
terminals.
Operating When each output from the Power Supply
(=H) Circuit Board has become inactive because of
turning off of the power switch or when the input
voltage has dropped below the rated voltage
value, "H" signal is sent to the BOARD ASSY.,
MAIN.
OFF The power switch is turned on and the Power
(=L) Supply Circuit Board Unit starts operating so
that each output becomes active.
"L" signal is sent to the BOARD ASSY., MAIN.
Operating Connected to the power switch on the Panel
Unit.
• These terminals are shorted when the switch
is ON. The Power Supply Circuit Board
becomes active.
Not These terminals are open when the switch is
operating OFF. The Power Supply Unit keeps operating
for about ten and several seconds to a few
minutes and then turns off.
Revision C
154