Unit Repair - C164 Main Board - Epson Stylus Pro Service Manual

Troubleshooting
5.4 UNIT REPAIR — C164 MAIN BOARD
This section describes the problems related to the main controller board (C164 MAIN). The table below
provides various symptoms, likely causes, and checkpoints. The checkpoints are waveforms, resistances, and
other values to be checked to evaluate the operation of each component.
Sy mpt om
Condition
The CPU
dose not
operate.
(Drive
system dose
not operate
The Printer
normally
dose not
when you
operate at
turn the
all.
printer on or
off.)
The carriage
The carriage
dose not
motor dose
operate
not operate
normally.
normally.
5-10
Table 5-7. Repair of the C164 MAIN
Cause
The reset circuit
dose not operate.
Selection of
control ROM is
abnormal.
Either CG or
RAM is defective.
CPU is defective.
IC2 is defective.
CP U
is defective.
Stylus Pro Service Manual
Checkpoint
Check the waveform of the +5V line
and that of the RESET signal.
Check pin 2 of IC3 for a change in
the signal HIGH/LOW.
Check the osillator signal at either
pin 75 or 74 of the CPU.
Check the serial signal output from
pin 25 or 28 of IC2 to the driver IC15.
Solution
Replace
IC13 or
IC8.
Replace
CG or
RA M .
If ssignal is
detected,
replace
CPU.
Otherwise
replace
CR 1 .
Replace
IC2.
Replace
t he CPU.
Rev.A