Chapter2 Operating Principles
Rev.A
2-23
2.2.2.1 Reset Circuits
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. Also, this circuit 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 C206 main board, 2 ICs are mounted ; IC for
monitoring the voltage level (logic line) and IC for monitoring the voltage level (power line) and both
are monitored by the gate array and CPU.
The figure below shows reset circuit block diagram with explanation on the next page.
[PST592(IC8)]
The actual operation of the circuit is to keep outputting Low signal until +5V line goes up to +4.2V
when the power is on, and to cancel the reset signal with output of High signal when the voltage goes up
more than 4.2V.
[M51955(IC9)]
This IC also performs as monitor on the power line same as the reset IC for logic described above.
High/Low is judged at the 33.2V.
[Relation between IC8 and IC9]
Reset signal which is low and output by IC9 is input to the CPU and gate array and system reset operation
is performed. Also, this signal is detected on the IC9(IC for reset monitor, power line) and outputs the
same Low signal towards CPU/NMI terminal by being input to NC5.
PST592D
(IC8)
Vcc
Vout
NRES
GND
+5V
C47
R138
+5V
R1
/RESET
TMP95C061
(IC1)
P85
E05B44
(IC2)
/RESET
174
30
16
1
2
3
4
M51955B
(IC9)
VCC
2
4
R6
+42V
R10
+5V
NC8
NC5
OUT
/NMI
10
P84
15
5
6
7
8
GND
IN
Figure 2-20. Reset Circuit Block Diagram
Summary of Contents for Stylus Color 400
Page 5: ...REVISION SHEET Revision Issued Data Contents Rev A February18 1997 First issue ...
Page 126: ...Chapter 6 Maintenance Rev A 6 5 No 1 No 2 10mm 2mm 2mm No 3 No 11 GEAR 34 ...
Page 138: ...EPSON Stylus Color400 Service Manual Rev A A 9 Figure A 3 C206 PSB Board Component Layout ...
Page 139: ...Appendix Rev A A 10 Figure A 4 C206 PSE Board Component Layout ...
Page 140: ...EPSON Stylus Color400 Service Manual Rev A A 11 Figure A 5 C206 PNL Component Layout ...
Page 141: ...Appendix Rev A A 12 A 5 Exploded Diagrams Figure A 6 Stylus Color 400 Exploded Diagram 1 ...
Page 143: ...Appendix Rev A A 14 Figure A 8 Stylus Color 400 Exploded Diagram 3 ...
Page 145: ...EPSON SEIKO EPSON CORPORATION ...