Fuser Hot Service Check - Lexmark Optra C710 Service Manual

5016-001

Fuser Hot Service Check

CAUTION: The fuser may be hot, use caution before removing or
servicing.
Error Codes 923 and 924 may display for a hot fuser failure.
Error Code 924 indicates the engine board has detected an open in
the thermistor circuit.
Note: Most of the wiring and electrical devices can be reached by
removing the paper exit cover on the bottom of the fuser assembly.
FRU
1 Fuser:
• Assembly
• Hot Roll
• Backup Roll
Bearings
2 Thermistor
Assembly
Engine Board
Action
Check the fuser assembly for signs of overheating
or damage, especially the hot roll and backup roll.
Also check for contaminants such as label glue or
excessive toner buildup.
• If contaminants are found, repair as necessary
or replace the fuser assembly.
• If damage from overheating is found, replace
the fuser.
Check for a shorted thermistor by measuring
across the connector located in the cable guide.
• If the thermistor is shorted, replace the
thermistor.
• If replacing the failing thermistor does not fix the
problem, replace the engine board.
Check for signs of damage or contamination to the
thermistor assembly. If no problem is found, check
the resistance of the thermistor.
Hot: CN18-1 to CN18-2:
Approximately 2.0k - 2.5k ohms
Cold: Approximately 150k to 250k ohms
If incorrect, replace the thermistor.
Check for an open in the thermistor circuit in the
fuser assembly. Be sure the thermistor is properly
connected to the thermistor cable in the bottom of
the cable guide.
Diagnostic Information
2-57