Epson LX-300 Service Manual

LX-300 Service Manual
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5.4 REPAIRING THE PRINTER MECHANISM
For detailed procedures for replacing or adjusting parts, refer to Chapter 3, Disassembly and
Assembly, and Chapter 4, Adjustments. If a problem or symptom recurs following an attempted
repair, refer to Table 5-10 to try find other potential causes.
Table 5-9. Repairing the Printer Mechanism
Problem
Symptom
Cause
Check Point
Solution
Foreign
substances
are lodged in
Manually move the timing belt
Remove the
the gears or to see if the motor can rotate
foreign
The CR motor elsewhere in
freely.
substances.
The CR motor assembly fails
the
assembly fails to operate the
mechanism”
10 operate.
iiming belt
Measure the motor coil
after power on.
me CR ~tor resistance. It should be about
Replace the
18 ohms. If the motor
is
CR motor
assembly is
shorted, also check the CR
assembly(and
defective.
drivers, if
motor assembly drivers on the
main board.
necessary).
The belt
Check for broken or worn
pulleys are
Replace the
The CR motor defective.
pulleys.
belt pulleys.
assembly
rotates, but
Check that the timing belt is Reinsert the
the carriage
inserted comctly into the timing
The timing
does not
bottom of the carriage.
belt.
belt is
The carriage move.
defective.
Replace the
does not
Check for a broken timing belt.
timing
operate when belt.
turned on
(after the
Clean and
carriage has
lubricate the
been
The carriage
The carriage
Check whether the caniage
CR guide
manually
moves to the
movement is
moves smoothly when moved
shaft
left slightly,
centered prior
not smooth. manually.
assembly.
to power on.)
then stops. Replace the
CR motor
assembly.
The carriage
moves to the
The HP
left or right
Use a multimeter to check the Replace the
sensor is
end, then defective.
HP sensor.
HP sensor.
stops.
The printhead
FFC common Check the common wires for
Replace the
wires are
the printhead FFC.
FFC.
Self-test
The carriage
disconnected.
printing is not moves, but
Measure the printhead coil
executed. does not print.
resistance. It should be
Replace the
~:a::nth=d approximately 33.3 ohms. If
printhead (and
the printhead is shorted, also
drivers, if
check the drivers.
necessary).
Rev.A 513

Epson LX-300 Specifications

General

Print Method	9-pin impact dot matrix
Interface	Parallel
Paper Handling	Friction feed, tractor feed
Weight	4.4 kg
Operating Environment	Temperature: 5 - 35°C, Humidity: 10 - 80%