I'm experiencing an erratic behaviour in the hot end temperature reading.
As you can see in the image attached during the heat-up - when the temperature rise constantly - the reading seems just fine.
When the target temperature (210°c) is reached the temperature reading become very unstable and swings between 190°c and 220°c in a very short time ( couple of seconds ), this is preventing the firmware to start printing.
I don't think the real hot end temperature can phisically change so fast so I suppose is the temp sensor failing, anyway I tried with the process of recalibrating PID parameters but the behavior remains the same.
Anybody experienced the same problem before? Any idea what to try next?
Any help is kindly appreciated.