Lexmark C 540n, Service Manual

Page: 82 / 262

2-48
Service Manual
5025-2xx, 4xx
Print quality—solid color page
Service tip: A solid color page is generally caused by a problem in the high-voltage
controller or an incorrect high-voltage in the printing process resulting in toner
development on the entire photoconductor drum.
Print quality—vertical banding
Replace the developer unit.
Step Questions / actions Yes No
1 Replace the photoconductor unit (part of the
imaging unit). Remove the imaging unit and
remove the developers. Place the original
developers in the new photoconductor, and
then replace the imaging unit. See
“Imaging
unit (IU) removal” .
Does this fix the problem?
Problem resolved. Go to step 2.
2
A faulty printhead can cause the problem. To
test the printhead for solid colors, place a
narrow strip of paper over the gap between the
developers. Make sure the paper stays in
place when you replace the imaging unit. This
will block the laser from discharging the
photoconductors. Print a Quality Test Page.
Does the page have a white vertical band?
Replace the printhead. See
“Printhead removal” on
page 4-65
.
Go to step 3.
3 Check the high-voltage contact from the HVPS
to the photoconductor charge roll. Ensure the
contact springs are properly mounted and that
the charge roll contact spring is making good
contact with the HPVS spring that runs through
the left printer frame. See
“Toner cartridge
contacts” on page 4-67 to view the proper
mounting and for removal procedures.
Are the spring(s) defective?
Replace the transfer contact
assembly. See
“Toner
cartridge contacts” on
page 4-67
.
Go to step 4.
4 Turn the printer off, and check the continuity of
the HVPS cable.
Is there continuity?
Go to step 5. Replace the cable
assembly.
5 Replace the HVPS. See “High-voltage power
supply (HVPS) assembly removal” on
page 4-35
.
Did this solve the problem?
Problem resolved. Replace the controller
board. See
“Controller
board removal” on
page 4-20
.