C206 Psb/Pse And C257 Psb/Pse Power Supply Board (For Stylus Color 440, 640, 740) - Epson Stylus Color 640 Service Manual

EPSON Stylus Color 440/640/740
2.2.1 C206 PSB/PSE and C257 PSB/PSE Power
Supply Board (for Stylus Color 440, 640, 740)
There are 2 types of power supply boards for Stylus Color 440/640/740.
The main components of the boards are the same, but the +5V
regulator ICs which create steady +5V are different. These boards are
power supply board with a RCC switching regulator, which generates
+42VDC for drive part and +5VDC for logic part to drive the printer. One
of the major characteristic of this board is that the same secondary
switch is used as Stylus Color series printer. By using this switch, the
following difference can be seen as superficial phenomena compared
with products applied with primary switch method, such as Stylus Color
IIs, II and Stylus 800/1000 series printer. The table below shows
application of voltages generated by C206 PSB/PSE board.
1. Even if the switch is turned off during the middle of printer operation,
since the driving power is turned off after the carriage goes back to
the carriage lock position, the possibility of clogging ink nozzle will
be decreased.
2. If the switch is turned off when the papers in the printer are still
being carried except for the papers in the hopper, the same
operation mentioned above is performed and the driving power is
turned off after the paper is completely ejected.
Table 2-8. Application of DC Voltage
Voltage
+42VDC CR Motor
PF/Pump Motor
Head driving power supply
+5VDC Power supply for logic control
System control signal
Sensor circuit power supply voltage
LED panel drive power supply
Nozzle selector control signal power supply voltage
Chapter 2 Operating Principles
Application
Figure 2-16 shows block diagram of C206 PSB/PSE board. The
process from the input of AC voltage to the output of 42 V DC and 5 V is
explained in the following pages.
+42 VDC
+5 VDC
IC51
+5V Regulator
+42VDC Line
Over Voltage
Limitation
ZD81-86,ZD51
+42VDC Line
Constant Control
C51
Smoothing
Circuit
D51
TRANS(T1)
C11
Smoothing
Circuit
Over Current
Filter Circiut
Protection
F1 L1,R1-2
C1-C4
AC Input
Figure 2-16. C206/C257PSB, PSE Board Block Diagram
Revision A
PSC Signal
from Main board
ZD53
+5VDC Line
Over Voltage
Limitation
ZD52,87
ZD90
+42VDC Lin Drop
Limitation Circuit
C84,Q84
Power Drop
Delay Circuit
PC1
Photo
Coupler
Q1 Q2,Q3,Q31
Abnormal
Main Switching
Feed back circuit
Circuit
Full Wave
Rectifier circuit
DB1
57