Lexmark C 540n, Service Manual

Page: 69 / 262

Diagnostic information
2-35
5025-2xx, 4xx
Operator panel display blank, printer beeps five times and pauses
Step Questions / actions Yes No
1 Turn the printer off, and remove the rear
shield. See
“Top cover assembly removal”
on page 4-13 .
Turn the printer on, and verify the following
values at JOPP1 on the controller board:
Are all these values approximately correct?
Go to step 2. Replace the controller
board. See
“Controller
board removal” on
page 4-20
.
2 Turn the printer off, and check for continuity in
the operator panel cable.
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?
Replace the operator panel.
See
“Operator panel logo
plate” on page 4-9 .
Replace the front cover
assembly. See
“Front
cover assembly removal”
on page 4-2
.
JOPP1
Pin Value
1 0 V dc
2 +5 V dc
3 0 V dc
4 Ground
5 +5 V dc
6 +3.3 V dc
7 Ground