Lexmark Optra K 4046, Service Manual

Page: 43 / 156

Diagnostic Information 2-13
Fuser Service Check
Image Quality Service Check
Before you troubleshoot a print quality problem, do the following:
•
Install another print unit if available
•
Use Tray 1 to test for quality of the base printer
Select the following settings. Be sure to note the original settings so
you can return the printer to the original setup.
•
Print Resolution: Set to 300 dpi (print quality problems should
be checked at different resolution settings)
•
Toner Saver: Set to off.
•
PQET: Set to off.
•
Print Darkness: Adjust knob to the middle setting.
FRU Action
1 920 Fuser
Error, Lamp
does not come
on Check the connection of the lamp cable at the
LVPS and at the thermal fuse. Be sure the lamp is
not burned out or broken.
Check the thermal fuse for conductivity. If the ther-
mal fuse conducts no current, replace the fuser.
If the connections are correct the lamp is good and
the thermal fuse is good. Replace the following
FRUs in the order shown:
1. LVPS
2. Engine Board
2 920 Fuser
Error, Lamp
does turn on Check the fuser for signs of excessive toner buildup
on the hot roll, backup roll, and thermistor. Be sure
the Thermistor is not bent, loose, or in the wrong
position. The thermistor should make contact with
the hot roll. Be sure the resistance of the thermistor
is between the range of 50 Ohms (hot) and 60k
Ohms (cold). If the resistance is out of this range,
replace the fuser. If you still have the problem
replace the following FRUs in the order shown:
1. LVPS
2. Engine Board