Lexmark T520 Service Manual page 84

Infoprint 1120 and 1125
FRU
2 Fuser Lamp
Fuser Top Cover Assembly
3 LVPS
LVPS to Fuser AC Cable
4 Fuser Top Cover Assembly
(Thermal Fuse/Thermistor
Assembly)
Action
Remove the controller board. Run
the Diagnostic Print Test and
observe the lamp through the left
side frame. If the lamp does not
come on, do the following:
• Remove the redrive assembly.
• Remove the fuser assembly,
disconnect the LVPS to fuser AC
cable from the fuser assembly
and remove the fuser.
• Verify that the lamp is installed
correctly. If correct, check the
continuity of the fuser top cover
assembly by verifying the lamp
contacts on the right contact
assembly. If incorrect, check
continuity of the fuser lamp. If
incorrect replace the lamp. If
correct replace the fuser top cover
assembly.
Caution: When taking
measurements for AC power,
observe all safety precautions.
Measure the AC line voltage
between the two connectors on the
fuser end of the LVPS to fuser AC
cable. If the voltage is incorrect, turn
the power off, and remove the LVPS.
Measure the AC line voltage
between pins CN1-1 and CN1-3 on
the board. If correct, check the
continuity of the LVPS to fuser AC
cable. If incorrect, replace the cable.
If the AC line voltage at CN1 is
incorrect, check fuse F2. If the fuse
is blown, replace the fuse. If the fuse
is not blown, replace the LVPS
assembly.
Disconnect the thermistor cable from
the fuser board at J2. Resistance:
• HOT J2-1 - J2-2 = 2.5K ohms
• COLD 150K ohms to 260K ohms
Diagnostic Information
2-57