EPSON Stylus COLOR C70/C80
Revision A
Operating Principles
Electrical Circuit Operating Principles
52
Figure 2-26. C424PSB/PSE Board Block Diagram
The C424 PSB/PSE board has the various control circuits to stop voltage output if a
malfunction occurs on the power supply board or the main board while the printer
mechanism is on duty. Following explains each control and protection circuit.
1.
Regardless of the state of the power switch (On or OFF), the voltage is always
applied to the primary side of the power supply board from the moment or at the
state that AC-plug is plugged in. At this time, F1 plays a role of preventing AC120
to 220V from coming into the F1.
L1 also prevents high harmonic wave noise generated in the RC circuit filter
which consists of C1 from going out, and eliminates the noise from outside here.
2.
The AC is full-wave rectified by the diode bridge DB1, and converted to
x
AC in voltage by the smoothing electrolytic capacitor C11.
3.
The pressured up direct current turns Q1 on through the starting resistor R18 and
R28 starts the primary side of the circuit.
4.
When the primary side is On, the energy (current) led by the electromagnetic
induction through the trans (T1) does not flow to the secondary side since the
diode (D51) on the secondary side is installed in the opposite direction.
5.
When the energy which is charged in the trans is reaching the saturated state, the
voltage which makes Q1 on becomes weak gradually. At the point that this voltage
drops at the certain voltage, C13 absorbs the current in the opposite direction and
Q1 is quickly shut off by the resulting sharp drop.
6.
When the primary side is turned off, the energy charged in the T1 is opened
according to the diode(D51) direction which is installed on the secondary side.
Basically, 42 V DC is output by these circuit operations and the number of T1
spiral coil.
7.
+5VDC is generated by pressured down this +42VDC as power supply. IC51
pressures down the +42VDC and generates p5VDC by chopping off the
output, forming the standard santooth wave form by the outer RCC integration
circuit.
The C424PSB/PSE board has the various control circuits to stop voltage output if a
malfunction occurs on the power supply board or the main board or while the printer
mechanism is on duty. Following explains each control and protection circuit.
+5V line over voltage protection circuit:
This protection circuit is in the same line as the +42V over voltage protection
circuit is located. The output voltage level of the +5V line is monitored by a Zener
diode.(ZD53) This circuit shuts down the +5V line forcefully when the voltage
level e7V.
+5VDC Line
Control Circuit
+42VDC Line
Over Voltage
Limitation
+42VDC Line
Drop Limitation
+42VDC Line
Constant
Control
Smoothing
Circuit
+5V Regulator
Power Drop
Delay Circuit
Photo Coupler
TRANS(T1)
PSC Sigual from
Main board
ZD53
+5VDC
+42VDC
IC51
Q91, ZD51
ZD52, 87
ZD90
C84, Q84
C51
Q1
C11
D51
Q2, Q31, Q32
Abnomal Feed
back circuit
Main
Switching
Circuit
Smoothing
Circuit
Over Current
Protection
Filter Circuit
Full Wave
Rectifier circuit
DB1
L1, C1
F1, TH1
AC Input
PC1
2
Содержание Stylus Color C70
Страница 1: ...EPSONStylusColorC70 C80 Color Inkjet Printer SEIJ01 004 SERVICE MANUAL ...
Страница 5: ...Revision Status Revision Issued Date Description A July 31 2001 First Release ...
Страница 9: ...C H A P T E R 1 PRODUCTDESCRIPTION ...
Страница 35: ...C H A P T E R 2 OPERATINGPRINCIPLES ...
Страница 60: ...C H A P T E R 3 TROUBLESHOOTING ...
Страница 96: ...C H A P T E R 4 DISASSEMBLYANDASSEMBLY ...
Страница 137: ...C H A P T E R 5 ADJUSTMENT ...
Страница 169: ...C H A P T E R 6 MAINTENANCE ...
Страница 182: ...C H A P T E R 7 APPENDIX ...
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