Lexmark W820 Service Manual page 43

4025-XXX
2.
Processing input information
Logic on the MCU compares the input information with the timing and reference
values that are stored in ROM and NVRAM on the PWB.
Example follows:
The Fuser Thermistor monitors the temperature of the Fuser Hot Roll and sends the
current temperature value to the I/O PWB. The I/O PWB relays the temperature data
to the MCU PWB. The MCU compares the current temperature with the set (or
expected) temperature that is stored in NVRAM on the MCU PWB. If the current
temperature is lower than the set temperature, the MCU sends a signal to the AC
Drive PWB to switch on the Fuser Heat Lamp until the current temperature reaches
the set temperature.
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General Information