Paper Select Sensor Service Check - Lexmark 2390 003 - B/W Dot-matrix Printer Service Manual

Paper Select Sensor Service Check

If form feed length is off by about 1 inch (25 mm), enter Setup Mode
and verify that the form length setting is correct. See the Setup
Mode and Switch Settings section.
FRU
1 Paper Select
Sensor
2-30
Action
Remove all paper from the printer and place
the tractor in the push position. Make sure the
Auto Sheet Feed (ASF) is set to OFF in the
Setup Mode.
Press Form Feed and time how long the gear
train rotates.
With the paper select lever in the cut sheet
position (sensor open) the gear train should
rotate for less than 2 seconds; with the lever in
the continuous forms position (sensor closed),
the gear train should rotate for more than 3
seconds. If the printer does not do this, inspect
the sensor to make sure it is being opened and
closed by the paper separator.
Disconnect CN5 from the sub logic board and
measure the paper selector sensor resistance
from CP5-1 to CP5-2.
Replace the sensor if the resistance does not
change from zero to infinite as the paper select
lever is moved from cut sheet to continuous
forms.
If the sensor is good but the gear train does not
run the right length of time, set the head gap to
position 1 and disconnect the short flexible
cable from CN3 on the main logic board.
Check the continuity between CP3-6 (paper
select sensor) and GND while actuating the
paper select lever.
Cut Sheet
23XX-001
1K ± 0.5K ohms
12K ± 0.5K ohms
If the resistance is correct, replace the main
logic board. If the resistance is incorrect,
replace the sub logic board.
Continuous Forms
23XX-002
0K ± 0.5K ohms
3.5K ± 0.5K ohms