Lexmark C520 Series, Service Manual

Page: 129 / 259

Diagnostic information
2-71
5022- xxx
Print quality—horizontal line
Print quality—insufficient fusing
Print quality—missing image at edge
Print quality—mottle (2 - 5mm speckles)
Print quality—narrow vertical line
Print quality—random marks
Service tip: The primary cause of random marks is due to loose material moving around inside the printer and
attaching to the photoconductor unit, developer roll, or transfer belt.
Potential cause Action
1 Photoconductor unit Photoconductor unit is defective. Replace photoconductor unit.
Potential cause Action
1 Fuser Ensure fuser has been properly installed. If so, replace fuser.
2 LVPS Replace LVPS. Go to “Low volt power supply (LVPS) removal” on
page 4-38 .
Potential cause Action
1 Developer cartridge Reseat developer cartidge.
Potential cause Action
1 Developer cartridge Keep running prints through and the problem normally clears up. If
the problem persists, replace developer cartridge.
Potential cause Action
1 Photoconductor unit Photoconductor unit is defective. Replace photoconductor unit.
2 Developer cartridge If replacing the photoconductor unit does not fix the problem, replace
the developer cartridge.
Potential cause Action
1 Photoconductor unit, devel-
oper roll (part of developer
cartridge), transfer belt
assembly Check for loose or foreign material that might be on the photoconduc-
tor unit. Check for loose or foreign material that might be on the
developer roll. Check the transfer belt assembly for any pieces of
material that are stuck to the belt.