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Horrors!!! Was about to fire up the printer to print some X'mas goodies but found that filament would not load.

Using a temp gun, the extruder does not go over 130°C when trying to load filament or in heating/cleaning mode. Display starts off showing extruder temp at 25°C, then goes all the way up to 230°C on the display although the extruder only gets up to around 130°C (and is unable to melt PLA). The extruder temperature seems to fluctuate going up and down between 80 - 130°C.

I've tried testing the thermistor (values were slightly out according to the temp/resistance table) and replaced it anyway with a new one with no change in results.

If I unplug the thermistor, the display shows 10°C (can anyone try this and confirm this?). When I plug it in, it shows 25°C (room temperature)

At this stage I'm thinking it's the logic board in the extruder module that's fried. I'm thinking that unplugging the thermistor should show an open circuit error or should show "-" as the extruder temperature? Can anyone confirm this?

Specific printer model is a Da Vinci Pro 1.0