Epson 440 - Manual (Page 67)

EPSON Stylus Color 440/640/740 Revision A
Chapter 2 Operating Principles 67
[C256 Main for Stylus Color 640]
The reset circuit prevents the CPU from running away, which is caused
by the unstable voltage in the logic line during the power ON/OFF
operation. And reset IC(IC9) monitors level of power voltage at the over
loading or malfunction on the circuit and manages the printer to operate
normally, keeping the damage to the printer minimum during the
abnormal situations. On the C256 main board.
Figure 2-21. Reset Circuit for Stylus Color 640
PST592D
(IC8)
Vcc
Vout
NRES
GND
+5V
C47
R138
+5V
R1
/RESET
TMP95C061
(IC1)
P85
E05B43
(IC2)
/RESET
174 30
16
1
2
3
4
M62030
(IC9)
VCC
2
4
R6
+42V
R10
+5V
NC8
NC5
OUT
/NMI
10
P84
15
5
6
7
8
GND
IN
Not mounted