Epson STYLUS Scan 2500 Service Manual page 56

EPSON Stylus Scan 2500
IC53
Operating Principles
SECONDARY SIDE
+3.3V +42V
IC151
+3.3V regulator
+24V
+12V
+42V line constant
control
IC52
+24V
regulator
+12V
Smoothing
regulator
circuit
D88 D89 D51
Transformer (T1)
AC input
Figure 2-22. B101 PSB/PSE Board Block Diagram
Electrical Circuit Operating Principles
+5V
ZD53
+5V line over
voltage limitation
IC51
ZD91
+5V regulator
+24V line over
voltage limitation
ZD52,87
+42VDC line over
voltage limitation
ZD51,ZD81-86
+24V line over
voltage limitation
ZD91
ZD42
+12V line over
voltage limitation
C51,C52
Power drop
delay circuit
C57,Q82,
Q84
C11
Q1
Main
Smoothing
switch-
circuit
Full wave
Filter circuit
Fuse
rectifier circuit
F1 L1, R1,
C1-4
Power signal
from MAIN
board/power
switch
PC1
Photo coupler
Feedback
circuit
Q2,Q3,Q
31,IC1
DB1
PRIMARY SIDE
Revision A
56