Operator Panel Display Is Dim And Unchanging - Lexmark C540 Service Manual

Operator panel display is dim and unchanging

Step Questions / actions
1 Turn the printer off, and remove the rear
shield. See "Rear shield removal" on
page 4-11.
Turn the printer on, and verify the following
values at JOPP1 on the controller board:
Pin
1
2
3
4
5
6
7
Are all these values approximately correct?
2 Check for continuity in the operator panel
cable connector.
Note: Remove the three screws holding the
operator panel, and place it facedown on top of
the printer. The cable connector pins will be
exposed and easier to contact.
Do all the conductors indicate continuity?
JOPP1
Value
0 V dc
+5 V dc
0 V dc
Ground
+5 V dc
+3.3 V dc
Ground
Yes
Go to step 2.
Replace the operator panel.
See "Operator panel
removal" on page 4-9.
5025-2xx, 4xx
No
Replace the controller
board. See "Controller
board removal" on
page 4-19.
Replace the front cover
assembly. See "Front
cover assembly removal"
on page 4-2.
2-41
Diagnostic information