Epson 2180 - LQ B/W Dot-matrix Printer Service Manual page 42

LQ-2180
Table 5-3. Repairing the C272MAIN Board (2/3)
Problem Cause
The printer does CRU1 is
not operate at all. defective.
IC11 or IC4 is
defective.
Carriage operation
is abnormal.
IC3 is
defective.
Troubleshooting
Checkpoint Solution
Check the oscillator signal at
pins 26 or 27 of the CRU1.
If the signal is
not correct,
replace IC4 (or
replace the main
board).
Otherwise,
replace CRU1.
Check input signal waveform
(CH1) at pins 1, 2, 3, and 4 of
IC4. Check output signal
waveform at pins 8, 1, 18,
If the input
and 11 of IC11.
signal is not
correct, replace
IC4 (or replace
the main board).
If the output
signal is not
correct, replace
IC11.
Check the output signal at If there is no
pins 68, 69, 70, and 71 of output signal,
IC3. replace IC3.
Repairing the C272MAIN Board
Table 5-4. Repairing the C272MAIN Board (3/3)
Problem Cause Checkpoint
• Check input signal waveform
at pins 1, 2, 23, and 24 of IC2.
• Check output signal waveform
at pins 6, 3, 18, and 21 of
IC1 is
IC12.
defective.
Paper feed is IC3 is
abnormal. defective.
IC2 is
defective.
• Check the output signal
waveform at pin 111 of IC3.
No data is IC3 is
printed., defective.,
• Check the voltage waveform
at pin HD1 - HD24 of IC3.
• Check the voltage waveform
(CH2) for each transistor.
IC3 is
defective or
A particular one of the head
dot fails to drive
print., transistors is
defective (Q4 -
Q27).
Revision A
Solution
If the input
signal is not
correct, replace
IC3. If the input
signal is correct
and the output
signal is not
correct, replace
the IC12.
If this signal is
not output,
replace IC3.
If the head drive
signal is not
output, replace
IC3. If the head
drive signal is
output, replace
the head drive
transistor.
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