Epson FX-980 - Impact Printer, Service Manual

Page: 55 / 72

FX-980 Revision A
Troubleshooting Repairing the C276 Main Board 55
Table 5-4. Repairing the C276 Main Board (2/3) Table 5-5. Repairing the C276 Main Board (3/3)
Problem Cause Checkpoint Solution
The printer does
not operate at all. CR1 is
defective. Check the oscillator signal at
pins 1 or 3 of the CR1. If the signal is
not correct,
replace the CR1
(or replace the
main board).
Otherwise,
replace IC2.
Carriage operation
is abnormal. IC9 or IC2 is
defective.
• Check input signal
waveform (CH1) at pins 6,
5, 17, and 16 of IC9.
• Check output signal
waveform (CH2) at pins 8,
1, 18, and 11 of IC9.
If the input
signal is not
correct, replace
IC2 (or replace
the main board).
If the output
signal is not
correct, replace
IC9.
Problem Cause Checkpoint Solution
Paper feed is
abnormal. IC1 is
defective.
IC12 is
defective.
• Check input signal waveform at
pins 1, 2, 23, and 24 of IC12.
• Check output signal waveform
at pins 6, 3, 18, and 21 of IC12.
If the input
signal is not
correct,
replace IC1 or
IC2. If the input
signal is
correct and the
output signal is
not correct,
replace the
IC12.
No data is
printed. IC2 is
defective. Check the output signal waveform
at pins 31 and 32. If this signal is
not output,
replace IC2.
A particular
dot fails to
print. IC1 is
defective or
one of the head
drive
transistors is
defective (Q2 -
Q19).
• Check the voltage waveform
(CH1) at port HD1 - HD18 of
IC1.
• Check the voltage waveform
(CH2) at the collector or emittor
side of each transistor.
If the head
drive signal is
not output,
replace IC1 (or
replace the
main board). If
the head drive
signal is
output, replace
the head drive
transistor.