Lexmark Optra T 4069 series Service Manual page 78

4069-XXX
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 Engine 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
Check the continuity from each pin
of J2 to ground. If there is continuity,
replace the fuser cover assembly
Error code 924 indicates the engine
board detects an open circuit in the
thermistor circuit for the fuser
assembly. The voltage on J2-6 on
the engine board measures
approximately +5 V dc. If incorrect,
replace the engine board. If correct,
check the continuity of the DC fuser
cable (fuser board to auto docking
connector) in the fuser assembly and
the DC fuser cable (engine board to
auto docking connector) in the
printer. If there is no continuity,
replace the cable. If there is
continuity, check the voltage on J2-2
on the fuser control board. It
measures approximately +5 V dc. If
incorrect, replace the fuser control
board.
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
2-49