Ricoh D109, Service Training

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S-C4L Training
74
Slide 74
Overheat Protection
‰
The BICU checks the fusing temperature through
the thermistor. The copier has five features to
safeguard the machine from overheating.
‰
Feature 1 prevents the machine from
overheating.
‰
Features 2 & 3 are fail-safe features.
‰
Features 4 & 5: See notes below.
Overheat Protection
Feature 1
ˆ
The BICU switches the fusing lamp off when the fusing temperature gets too
high.
Feature 2
ˆ
The BICU (Base engine & Image Control Unit) stops the machine when the
thermistor detects an abnormal condition. Then the machine will show one of
these SC codes: SC 543, SC 544, SC 545, SC 546
Feature 3
ˆ
The BICU stops the machine if the thermistor does not work correctly. Then the
copier shows SC 541
Feature 4
ˆ
The thermostat near the center cuts power to the fusing lamp at 160ºC. The
thermoswitch near the end cuts power to the fusing lamp at 170ºC. These
thermoswitches are on the same circuit as the fusing lamp.
Feature 5
ˆ
The BICU stops the machine if the exhaust fan does not work correctly. Then the
machine shows SC 590.
ˆ
A defective exhaust fan could cause the machine to overheat.