Epson 2180 Service Manual - Page 26

System Reset Circuit - main board

Page 26 highlights

LQ-2180 The following table lists the each function of the main components of the C272 MAIN board. Table 2-1. Functions of the Main Board IC Name Location Function CPU IC4 Detects conditions of various sensors and controls phase change for the CR motor. Gate Array Control the functions below: • Memory management IC3 • Printhead drive • Phase change for the PF motor EEPROM Contains such information as the factory IC5 setting values for the various adjustments and the operational record of the printer. ROM IC10 Contains the control program. RAM Manages the following functions: • Buffer used to receive data IC8 • Data Extension • CPU working area CG-ROM IC7 Contains font data. SLA7024M IC11 Constant current drive IC for CR Motor A2917 IC12 Constant current drive IC for PF Motor Revision A 2.1.2 System Reset Circuit The reset IC (IC2) outputs a reset signal under the conditions below to feed back the status to the CPU and the gate array: † The printer is turned on or off. † The voltage level drops due to abnormal condition. Receiving the signal, the CPU and the gate array immediately shut off the operation of each IC to prevent the printer from falling into abnormal status caused by unstable power supply. P S T 5 9 2 (IC 2 ) V out 1 M RES 2 V cc 3 GND 4 C P U (IC 4 ) 2 3 /R S T G .A (IC 3 ) 7 4 /R S T Figure 2-3. Reset Circuit Operating Principles Control Circuit 26

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56

LQ-2180
Revision A
Operating Principles
Control Circuit
26
The following table lists the each function of the main components of
the C272 MAIN board.
Table 2-1.
Functions of the Main Board
2.1.2
System Reset Circuit
The reset IC (IC2) outputs a reset signal under the conditions below to
feed back the status to the CPU and the gate array:
°
The printer is turned on or off.
°
The voltage level drops due to abnormal condition.
Receiving the signal, the CPU and the gate array immediately shut off
the operation of each IC to prevent the printer from falling into abnormal
status caused by unstable power supply.
Figure 2-3.
Reset Circuit
IC Name
Location
Function
CPU
IC4
Detects conditions of various sensors and
controls phase change for the CR motor.
Gate Array
IC3
Control the functions below:
Memory management
Printhead drive
Phase change for the PF motor
EEPROM
IC5
Contains such information as the factory
setting values for the various adjustments
and the operational record of the printer.
ROM
IC10
Contains the control program.
RAM
IC8
Manages the following functions:
Buffer used to receive data
Data Extension
CPU working area
CG-ROM
IC7
Contains font data.
SLA7024M
IC11
Constant current drive IC for CR Motor
A2917
IC12
Constant current drive IC for PF Motor
G
.A
( IC
1
2
3
4
P
S
T 5 9 2 ( IC
2)
V
out
M
R
E
S
V
cc
G
N
D
C
P
U
(I
23
/R
S
T
74
/R
S
T