Hot Fuser Service Check - Lexmark T620 Service Manual

4069-5XX/7XX

Hot Fuser Service Check

Error codes 923 and 924 may display for a hot fuser failure.
CAUTION: The fuser may be hot, use caution before removing or
servicing.
FRU
1 Fuser Cover Assembly
(Assembly includes
Thermistor and Thermal
Fuses.)
2 System Board
3 Fuser Hot Roll
Backup Roll Bearings
Action
Check for damage to the thermistor
assembly. Check the resistance of
the thermistor:
HOT - J2-1 to J2-2 = 2.5K ohms
COLD =150K ohms to 260K ohms
If the resistance is incorrect, replace
the fuser cover assembly.
Error code 924 indicates the system
board detects an open circuit in the
thermistor circuit for the fuser
assembly. The voltage on J14-6 on
the system board measures
approximately +5 V dc. If incorrect,
replace the system board. If correct,
check the continuity of the DC fuser
cable in the fuser assembly and the
DC fuser cable (system board to
auto docking connector) attached to
J14 on the system board. If there is
no continuity, replace the cable.
Examine the fuser assembly for
signs of overheating or damage.
Check the hot roll and backup roll for
signs of excessive toner, label glue,
labels or other contaminants. If any
are found, repair as necessary or
replace the fuser assembly.
Diagnostic Information
2-67