Thermistor/Heater Status Counter Control - Toshiba e-STUDIO453 Service Manual

(5) Thermistor/Heater status counter control
• To enhance the safety of the fusing section unit, CPU provides the following protection: When
the third [C410] error has occurred after two consecutive [C410] errors, the IH coil is not turned
ON and error [C410] is displayed immediately even if an operator turns OFF the power and
back ON.
However, if the equipment goes into a ready state normally with the thermistor/heater status
counter "1" or below, the counter is cleared to "0".
• If the error codes [C410] to [C450] are displayed and still not cleared even though the thermis-
tor, thermostat and IH coil have been repaired (and the power ON/OFF does not clear the er-
Reference
*The thermistor/heater status counter never has values other than 0-18.
• If the IH coil does not turn ON and the service call [C410] is displayed immediately after the
power is ON, ensure the thermistor/heater status counter is "2" or over. If it is "2" or over, be
sure to check the thermistor, thermostat and IH coil. Reset the counter to "0" (Setting Mode
(08-400)) after repairing them, then turn ON the power.
• If the thermistor/heater status counter is "19" or over (e.g., 21), the data in NVRAM or
NVRAM itself may possibly have been ruined due to causes such as leakage from the char-
gers. Check the bias, high-voltage transformers and charge wires to see if any of them is
defective, and also look through all the data in the NVRAM.
• When the thermistors detect overheating, the CPU decides the error code and counter value
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of the fuser roller thermistor status. After turning OFF each output (the IH coil, exposure
lamp, control panel display, motors and so on), the CPU turns OFF the power to protect the
fuser unit.
Error code: C440 ([C] and [8])
Counter value of the fuser roller thermistor status: 9 (08-400)
Thermistors continue detecting the abnormal temperature even after the error codes and
counter values are decided. Even if the power is turned ON immediately, it is automatically
turned OFF again when the surface temperature of the fuser roller is still higher than the
abnormal temperature detected.
Wait until the surface temperature of the fuser roller is lowered enough, and turn ON the
power to check the counter value while it is turned OFF again. After confirming that it is the
IH control abnormality, correct the abnormality and clear the counter value (08-400) to "0" to
start up the equipment normally.
e-STUDIO350/352/353/450/452/453
FUSER UNIT / PAPER EXIT SECTION
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