Lexmark 2390 003 - B/W Dot-matrix Printer Service Manual page 53

FRU / Symptom
6 Paper Select
Sensor
7 Pull Tractor
Sensor
8 Main Logic Board
Action
Remove all paper from the printer and place
the tractor in the push position.
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.
If the pull tractor sensor has failed to close,
Park/Load and Auto Tear Off will not work
when using push tractors.
If the sensor has failed to open, Park/Load will
try to park paper when using pull tractors, but
the paper will feed all the way out of the
tractors and cannot reload. Refer to the
Tractor Sensor Service Check" on page
If no other problem is found replace the main
logic board. Reset the "Bidirectional Print
Adjustment" on page 4-5.
Diagnostic Information 2-29
"Pull
2-38.