Repair Of The Printer Mechanism - Epson LQ-870 Service Manual

5.5 REPAIR OF THE PRINTER MECHANISM

for detailed procedures for replacing or adjusting parts, refer to Chapter
4, Adjustment.
and Chapter
5-5
to try to find other potential causes.
Problem
The carriage motor The carriage motor
completely fails to
fails to operate.
activate at power
on.
The carriage does The carriage motor
not operate nor- rotates, but the
carriage does not
(after the carriage
move.
has been manually
centered prior to
power on).
The carriage
moves left slightly,
then stops.
The carriage
moves to the left
or right end, then
stops.
Self-test printing The carriage
does not execute. moves, but no
printing is
performed.
If a problem or symptom recurs following an attempted repair, refer to Table
Table 5-6. Repair
of
Symptom Cause
Foreign substances
are lodged in the
gears or elsewhere
in the mechanism.
The carriage motor
is defective.
The belt pulley is
defective.
The timing belt is
defective.
Carriage move-
ment is not
smooth.
The home position
sensor is defective.
The printhead FFC
common wires are
disconnected.
5-19
3, Disassembly and Assembly,
the Printer Mechanism
Checkpoint
Manually move the
timing belt to see if
this causes the mo-
tor to rotate.
Measure the coil re-
tor. The resistance
should be about
5.0 ohms.
Check for broken
or worn pulley.
Check that the tim-
ing belt is correctly
inset-ted into the
bottom of the
carriage.
Check for a broken
timing belt.
Check whether the
carriage moves
smoothly when
moved manually.
Use a multimeter to
check the home-po-
Check the common
wires for the print-
head FFC.
REV.-A
Solution
Remove any for-
eign substances.
Replace the car-
riage motor.
Replace the belt
pulley.
Reinsert the timing
belt.
Replace the timing
belt.
Clean and
lubricate.
Replace the home-
position sensor.
Replace the FFC.