Lexmark C750 Service Manual page 117

Multipurpose feeder (MPF)—no media in MPF
A 250 Paper Jam indicates that the MPF tried to feed a sheet of media from the MPF tray. A 250 Paper Jam may
occur when there is no paper in the MPF, MPF is selected as the paper source, or the MFP sensor is
malfunctioning. If media is in the MFP it may feed normally with no 250 Paper Jam even though the sensor is
malfunctioning.
Step Action and questions
1 Enter the Diagnostics Menu. Select Input Tray Tests,
Sensor Test, and Multipurpose Feeder. Manually
actuate the MP sensor by moving the paper flag in the
MPF.
Does the test pass?
2 Make sure that the MPF sensor cable from the engine
board is correctly installed at J70 on the engine board.
Is the cable correctly installed?
3 Check the cable connection between the MP sensor
cable and the sensor.
Is the connection good between the two cables?
4 Disconnect the sensor cable from J70 on the engine
board.
Measure the following voltages on J70, being careful
not to short any adjacent pins in the connector. All
voltages are approximate values.
Connector pin Voltage
J70-1 +5 V dc
J70-2 +5 V dc
J70-3 +5 V dc
J70-4 0 V dc
Are the voltages correct?
5 Check continuity of the sensor cable that is between
the engine board and MPF assembly.
Is there continuity?
Yes No
Replace the MPF Go to step 2
assembly. See
"Multipurpose
feeder (MPF)
removal" on
page 4-40.
Go to step 3 Install the cable
correctly
Go to step 4 Install the cable
correctly
Go to step 5 Replace the engine
board. See
"Engine board
removal" on
page
Replace the sensor Replace the sensor
assembly. cable assembly.
Diagnostic information
5060-00x
4-29.
2-83