Epson FX-880 Service Manual page 121

Troubleshooting
Symptom Condition
The printer The CPU does
does not not operate.
operate.
5-18
Table 5-12. Repairing the C229 Main Board Assembly
Possible
Cause
Defective
operation of the
reset circuit.
The ROM
selection jumper
is defective.
Checkpoint
While turning on the power,
check the voltage waveforms
for the +5 VDC line (pin 3 of
IC1) and the reset signal (pin
1 of IC1). You can use pin 4
as the ground.
5V line
/RESET
Check the signal waveform
at pin 22 of IC7 and pin 30 of
IC6. (The signal should be
present at one pin, but not
the other.) You may use pin
15 as the ground.
EPSON FX-880/FX-1180 Service Manual
Solution
Replace the main
board.
Replace the
power supply
board.