Print Quality Service Check - Lexmark C746n Service Manual

Step Questions / actions
Check the operator panel assembly cable.
2
Is the cable damaged?
Stripes display, distorted display, and other display issues
Step Questions / actions
1. Turn off the printer.
1
2. Open the rear cover.
3. Reseat the operator panel cable (J2) on
the system board.
4. Check the J2 connector on the system
board for any damage.
Is the connector damaged?
1. Turn off the printer.
2
2. Disconnect the J2 operator panel cable.
3. Connect a new top access cover
assembly from outside of the machine for
verification.
Does the problem persist?
1. Open the top access cover assembly,
3
Refer to
"Top access cover assembly
removal" on page
2. Reseat the operator panel cable on both
ends.
3. Check for any damage on the cable.
Is the cable damaged?
• For C746x:
4
Replace the 2.3 inch operator panel
assembly with card. See
assembly removal (C746)" on
page 4-34.
• For C748x:
Replace the UICC card. See
panel assembly removal (C748)" on
page 4-37.
Does the problem persist?
Replace the LCD panel.
5
Does the problem persist?
Replace the Operator panel cable.
6
Does the problem persist?

Print quality service check

Note: This symptom may require replacement of one or more CRUs (Customer Replaceable Units) designated
as supplies or maintenance items, which are the responsibility of the customer. With the customer's permission,
you may need to install a developer (toner) cartridge or photoconductor unit.
Replace the top cover
access assembly. See
"Top access cover
assembly removal" on
page
Replace the system board.
See
removal" on page
Return to the Old Top
access cover assembly,
then go to step 6.
Replace operator panel
cable. See
4-54. panel cable removal" on
page
"Operator panel
"Operator
Go to step 6.
For dead display. Go to
Dead printer service check.
Replace the system board.
See
removal" on page
Yes
4-54.
Yes
"System board
4-163.
"Operator
4-140.
• For C746x:
Return the old 2.3 inch
operator panel
assembly with card,
then go to step 6.
• For C748x:
Return the old UICC
card, then go to step 5.
"System board
4-163.
Diagnostic information
5026
No
Replace the system board.
See
"System board
removal" on page 4-163.
No
Go to step 2.
Return to the Old Top
access cover assembly,
then go to step 3.
Go to step 4.
Problem resolved.
Problem resolved.
Problem resolved.
2-131
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