Epson Stylus 1500, Service Manual

Page: 59 / 185

Main Control Circuit Operating Principles
The main control circuit for this printer is the C172 MAIN board, which is controlled by a 16-bit
TMP96C061AF CPU (IC1) running at 24.57 MHz. A 4M DRAM (CAS method) on this board is
controlled by the CPU itself. The CPU also manages the Type-B interface control.
Gate array E05B16 (IC2) manages the printhead driver, the external Centronics
®
parallel I/F, the
control panel, and the motor drivers.
This board is also equipped with a 93C46 EEPROM (IC11) to store parameters such as the printer
mechanism control parameter, default setting parameters, and the special counter value used for
printhead (ink management) protection.
The NJU6355E timer IC (IC10) counts each time the printer is cleaned and keeps track of how long
the printer is not used, thereby allowing the printer to be cleaned only when necessary.
C L K
SD I/O
Data Bus
DRAM
(IC17)
Address Bus
EEP RO M
(IC11)
93C46
Reset IC
for Power
(IC8)
M51955B
N J U 63 5 5 E
(Timer
Counter)
(IC10)
(IC9)
PST592D
To
A
To B
TMP95C061AF
(IC1)
C P U
E05B16
(IC2)
CG-ROM
(IC7)
PROM(4M)
(IC3)
PRO M
(IC4)
CG-ROM
(IC6)
From A
SED 6 10 0 D0 A
(U1)
PF Motor
Driver Circuit (IC16)
SED5 6 1 9 D0 A
(U1)
From B
DRAM
(IC18)
From B
+42 VDC
+ 5 VDC
Type-B I/F
+5 V
Panel
Reset IC
for Logic
Lithium
Battery
P S C
Sensor
Bl
a
c
k
/ Co
lo
r
No
zzl
e S
e
le
c
ti
o
n
C
R
M
o
to
r /
P
F
M
o
to
r
C
o
n
tro
l
Pa
ra
ll
e
l I
/F
Black/ Color Nozzle Selection
Black / Color
Common Drive Circuit
CR Motor
PF Motor
Carriage Unit
Black Head
(64 Nozzles)
Color Head
(Option)
CR Motor
Driver Circuit (C15)
Figure 2-20. Main Control Circuit Block Diagram
Operating Principles
2-18 Rev. A