Minolta Di450 Service Manual page 241

C0520
Step
1 Upper Fusing Roller Heater Lamp is ON even
after the copier has completed warming up. Or
Lower Fusing Roller Heater Lamp is ON when
the surface temperature of Lower Fusing Roller
Heater Lamp is 140°C or more as indicated on
"Level History" under the Tech. Rep. mode.
2 Upper and Lower Fusing Roller Thermistors
are installed properly.
3 Upper and Lower Fusing Roller Thermistors
are dirty.
4 Upper Fusing Roller Thermistor operation: the
resistance across CN217-2 and 3 on the Fus-
ing Unit end is infinity with CN217 (4P) discon-
nected.
5 Lower Fusing Roller Thermistor operation: the
resistance across CN218-2 and 3 on the Fus-
ing Unit end is infinity with CN218 (4P) discon-
nected.
Check
T-50
Result Action
YES Change DC Power Supply
Main.
NO Reinstall.
NO Clean.
YES Change Upper Fusing
Roller Thermistor.
YES Change Lower Fusing
Roller Thermistor.