Service manual

Troubleshooting
5-20
EPSON FX-880/FX-1180 Service Manual
Table 5-12. Repairing the C229 Main Board Assembly (continued)
Symptom Condition
Possible
Cause
Checkpoint Solution
Paper feeds
abnormally
Paper does not
feed
IC11 is
defective.
Check the paper feed motor
phase control signals at pins
1, 2, 23, and 24 of IC11; also
check the motor drive signals
at pins 3, 6, 18, and 21 of
IC11. Any pin 7-17 may be
used as the ground, or use
the chassis frame.
Pin 1 of IC11
Pin 3 of IC 8
Replace the main
board.
Self-test
printing is
abnormal.
The self-test does
not execute, or
the printer does
not print a
particular dot.
❏
One of the
transistors
between Q2
and Q10 is
defective.
❏
One of the
transistors
between Q11
and Q25 is
defective.
Check the printhead drive
signal at the collector and
base of Q2 through Q10. In
each case, the emitter may
be used as the ground.
BASE of Q5
CORRECTOR of Q5
Replace the main
board.
Data from the
host prints
incorrectly.
Data corruption
occurs when the
interface is used.
The CPU or IC2
is defective.
COLLECTOR OF Q5