Epson FX-2170 Service Manual page 135

Troubleshooting
Table 5-7. Repairing the C166 MAIN Board Assembly
Problem
IC1 is defective. IC2 is
defective. IC11 is
defective.
Paper feed is
abnormal.
IC1 is defective.
No data is
printed.
IC2 is defective.
One of the head drive
transistors is defective
(Q5 ~ Q13, Q14 ~
Q22).
A particular
dot fails to
print.
5-14
Cause
Check input signal waveform at pins 43
and 26 of IC11.
Check output signal waveform at pins 6,
3, 18, and 21.
Check the output signal waveform at pin
19 of IC1.
Check the voltage waveform (CH1) at
pin 69 and pins 76 ~ 93 of IC2.
Check the voltage waveform (CH2) for
each transistor.
FX-2170 Service Manual
Checkpoint Solution
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 IC11.
If this signal is
not output,
replace IC1.
If the head drive
signal is not
output, replace
IC2. If the head
drive signal is
output, replace
the head drive
transistor.
Rev. A