Epson Stylus 1500 - Unit Repair - C172 Main Board

UNIT REPAIR — C172 MAIN BOARD
This section is necessary only for servicers who repair to the component level. Servicers who
perform only board replacement (including all U.S. servicers) can ignore this section. The table
below lets you troubleshoot problems with the main controller board (C172 MAIN). This table
provides various symptoms, likely causes, and checkpoints. Checkpoints include waveforms,
resistances, and other values to be checked to evaluate the operation of each component.
Table 5-6. Repair of the C172 MAIN Board
Symptom
Condition
Cause
Checkpoint
Solution
The printer
does not move
at all.
The CPU
does not
operate.
(Drive system
does not
operate
normally
when turn
the printer on
and off.)
The reset circuit
does not operate.
Replace
IC8 or
IC9.
Selection of
control ROM is
abnormal.
Check the pin 2 of IC3 for a
change in the signal HIGH/LOW.
Replace
MAIN.
board
CG-ROM or
RAM is defective.
Replace
CG-ROM
or RAM.
CPU is
defective.
Check the osillator signal at either
pin 27 or pin 28 of the CPU.
Replace
CPU or
MAIN.
board
The carriage
does not
operate
normally.
The carriage
motor does
not operate
normally.
IC2 is defective.
Check the waveforms of IC15
pin 6 or 17.
Replace
IC2.
CPU is defective.
Replace
IC2 or
MAIN.
board
Check the waveform of the +5 V
line and that of the RESET signal.
Troubleshooting
5-12 EPSON Stylus 1500 Service Manual