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Cc#of
&mdce
Manual
2.3.2.1 Reset Circuits
The
C137
MAIN board
contains
2 reset circuits: the
+5V
monitor reset circuit and the
+35V
monitor
reset circuit. The
+5V
monitor reset circuit monitors the voltage
level
of the
+5V
line,
using reset
IC
@
PST592D
(IC12),
and outputs a reset signal to the
E05A96
gate array
(IQ
when the voltage level
drops below
+4.2V.
The
+35V
monitor reset arcuit
monitors the
voltage level of the
+35V
line,
using reset
IC
M51955B
(IC8),
and outputs a reset signal to the CPU.
The
reset signal is generated
when the voltage level drops
below
+28V,
and this causes a
non-maskable
interrupt (NM).
+35V
L
+5V
+
+5V
CPU
(ICI)
M51 9556
.
(IC8)
‘6
72•
NMI
PA8
68+
P62
71
b
RES
E05A96
(IC2I
L
1
Figure 2-19. Reset
2.3.2.2 Sensor Circuits
-#
RST
Type B
Circuit Block Diagram
@
‘. .,-
The following sensor circuits enable the
C137
MAW board to monitor printer mechanism status:
HP sensor
A
photocoupler-type
HP (home position)
sensor is
attachd
to the
surfam
of the
printer mechanism to detect the carriage home position. A LOW level from the
signal indicates that the carriage is m home position.
PE sensor A
mechanical switch PE (paper end) sensor is built into the printer
mechanism to
determine whether there is paper in the printer or not. A LOW level
hm
the
signal
indicates that no paper is loaded.
CO sensor
A micro switch is attached to the bottom of each ink cartridge holder in the carriage
unit. When the ink cartridge is installed, these switches are pressed and a LOW
level from the signal
indiates
that the ink cartridge is installed into the ink
cartridge holder.
Thermistor
c
;
A thermistor is attached to the color printhead driver board to monitor its
*.
temperature. The
CPU changes the
print&ad
drive signal’s pulse width (charge
pulse width) based on the temperature level.
+5V
+5V
CPU (lCl)
-
[
1
h
(CN8)
“
02
Y
~
AN1
AN2
e
~
TH
-
>
90
AN5
● “
86
70
cco-
[
:
“
:
‘b
HP
o
;
ANO
AN4
4 “ 70
~~o
(CN9)
3
h
Figure 2“20.
1
I
Sensor Circuit Block
Diagram
(CN12)
(CN1l)
2-16
Rev. A