Reset Circuits; Sensorcircuits; Figure 2-19. Reset Circuit Block Diagram - Epson 4003353 Service Manual

2.3.2.1 Reset Circuits

The C137 MAIN board contains
reset circuit. The +5V monitor reset circuit monitors the voltage level of the +5V line,
drops below +4.2V. The +35V monitor reset arcuit
using reset IC M51955B (IC8), and outputs a reset signal to the CPU. The reset signal is generated
when the voltage level drops
M51 9556
L
Figure 2-19. Reset
2.3.2.2 Sensor Circuits
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
determine whether there is paper in the printer or not.
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
A thermistor is attached to the color
temperature. The
pulse width) based on the temperature level.
0
"
[
HP o ;
[
Figure 2"20.
2-16
2 reset circuits: the +5V monitor reset circuit and the +35V monitor
monitors the
below +28V, and this causes a non-maskable interrupt (NM).
.
'6
Circuit Block Diagram
CPU changes the print&ad drive signal's pulse width (charge
CPU (lCl)
1
2
86
ANO
3
:
"
Sensor Circuit Block Diagram
Sty/us Cc#of &mdce Manual
voltage level of the +35V line,
(ICI)
CPU
RST
PA8
Type B
A LOW
printhead
driver board to monitor its
-
AN2 e ~ TH
AN5 "
4 " 70 ~~o
AN4
I
using reset IC
mechanism to
level hm the
-
Rev. A
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