Lexmark C750 Service Manual page 137

Step Actions and questions
4 Output Expander control board check—disconnect the
motor cable J4 and check the voltages at J4 on the
board. Warning: Be careful not to short to adjacent
pins on the connector.
The voltages measure approximate.
Pins Voltages (motor idle)
J4-1 +24 V dc
J4-2 +24 V dc
J4-3 +5 V dc
J4-4 +5 V dc
Are the voltages correct?
Finisher
Step Actions and questions
1 Make sure the top options cable is correctly plugged
into the system board.
Is the cable correctly installed?
2 Make sure the finisher cable is correctly installed on top
of the printer.
Is the cable correctly installed?
3 Make sure the finisher cable is correctly installed on the
finisher system board.
Is the cable correctly installed?
4 When 990 error is installed, press and hold Return and
Select to view the sub error code.
Scroll down with Menu to see the additional display
lines and view the value at the indicated position (EQC
and DB1) and match the information to the table below.
Finisher (Bin 1) - No other output options
26 9D
DB1 DB2
DB5 DB6
Does the information on the table help find the
problem?
EQC DB1 Explanation
45 05 Jogger motor homing timeout error. Obstruction in Jogger, motor or sensor failure.
4C 0C Offset motor timeout error. No clearance around output bin, motor or sensor failure.
50 10 Stapler unit is removed. Cable harness to stapler damaged or disconnected.
81 EQC
DB3 DB4
DB7
Yes No
Replace the Output Replace the
Expander control mechanical
board linkage/DC motor
assembly
Yes No
Go to step 2 Install correctly
Go to step 3 Install correctly
Go to step 4 Install correctly
Repair the finisher Contact your next
as indicated in the level of support.
table.
Diagnostic information
5060-00x
2-103