Canon CP660 Service Manual page 217

e. The sensitivity of the thermsitor (Note 2) is on the high temperature side at power-on
(during initial state), but the upper and lower fixing roller detection signals (FXTHU,
FXTHL) are 60°C or less. The thermistor sensitivity is switched from the high to the
lower temperature side.
At this time, either FXTHU or FXTHL is -10°C or less. (thermistor open circuit)
However, if both FXTHU and FXTHL are -10°C or less, the absence of the fixing
assembly will be indicated (E813).
:
Caution
1. If an error high or low temperature is detected, the M-CPU uses the D-CPU to store
a fixing heater error in the error memory capacitor (C259).
Once this happens, turn off the power once, leave the printer unit alone for 30 min
or more, and turn on the power once again to reset the printer unit.
2. Switching the Thermistor Sensitivity
The machine's M-PCU switches the thermistor sensitivity (between low-tempera-
ture sensitive mode and high-temperature sensitive mode) to ensure accurate
detection regardless of the range of temperature (low or high) using the thermistor
sensitivity switch signal (FXSEL). When the FXSEL signal is '0', the thermistor will
be in low-temperature detection mode; when '1', high-temperature detection mode.
COPYRIGHT © 1999 CANON INC.
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CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 6 FIXING SYSTEM
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