Lexmark 2390 003 - B/W Dot-matrix Printer Service Manual page 57

FRU
3 Op-Panel
Op-Panel Cable
4 Carrier Motor
5 Paper Feed Motor
6 Printhead
Printhead Cables
7 Main Logic Board
Action
If there is still a power LED problem, check the
operator panel cable continuity and replace the
cable or the operator panel.
Disconnect the carrier motor from main logic
board CN9 and turn the printer off and then on.
If the power LED lights correctly only with the
carrier motor disconnected, replace the carrier
motor.
Disconnect the paper feed motor from main
logic board CN10 and turn the printer off and
then on. If the power LED lights correctly only
with the paper feed motor disconnected,
replace the paper feed motor.
Disconnect the printhead cable from the sub
logic board and turn the printer on. If the power
LED lights correctly only with the printhead
cables disconnected from the sub logic board,
there is a short in the printhead or printhead
cables.
Disconnect the printhead cable from the sub
logic board and make sure none of the leads
on the cable are shorted to ground.
If no problem is found with other components
but the printer still has a power problem,
replace the main logic board.
Reset the bidirectional print adjustment; refer
to "Bidirectional Print Adjustment" on page 4-5.
Diagnostic Information 2-33