Top Of Forms Problem Service Check - Lexmark 2390 003 - B/W Dot-matrix Printer Service Manual

Top of Forms Problem Service Check

Note: This service check applies to the 23XX-002 and 23XX-003
printers only. 23XX-001 machines have a single paper sensor that
serves as a paper empty sensor and also determines the top of form
setting. For top of forms problems on 23XX-001 printers, refer to the
"Paper Empty Sensor Service Check" on page
23XX-002 and 23XX-003 machines have two sensors:
•
The left sensor is paper empty.
•
The right sensor is top of form.
FRU
1 Top of Form
Sensor
2 Main Logic Board
Action
Check that the top of form sensor and its flag
are properly installed and are undamaged.
Remove the paper and set the paper select
lever to the cut sheet position and turn the
power on.
Measure the voltage between main logic board
CN8-2 (TOF signal) and CN8-3 (GND).
• When there is paper in the printer the
voltage should be 0 V dc.
• When there is no paper in the printer the
voltage should be 5 V dc.
Replace the sensor if the voltage is incorrect.
Replace the main logic board if the voltage is
correct and there is still a problem.
Reset the "Bidirectional Print Adjustment" on
page 4-5.
Diagnostic Information 2-39
2-26.