Wild fluctuations in extruder temperature, has anyone encountered this?

Wild fluctuations in extruder temperature, has anyone encountered this? I am using and e3d with 24v power to cartridge heater. I have run PID calibration and it is very stable when just sitting idle, but when it starts printing it goes crazy.

Could it be electrical interference from the motors? I put a ferrite bead on the sensor line but it does not seem to help.

Watching the video I have to wonder if your thermistor is bad. There isn’t any way you could actually be having these swings the block can’t heat and cool that fast.

I agree that it is likely a sensor issue

I spend exactly the same, my thermistor was making poor contact. sorry for my bad English

I agree to. Changing thermistor, may have a big possibility to resolve the problem.

Or it could be your right on the edge with your power supply

Thanks for the advice, I’ll replace the thermistor as the first step. Pretty sure I have a spare laying around somewhere.

I would bet on a defective thermistor as well

I had a thermistor with a broken wire about 3 inchs from hot end under the thermal insulation which I reconnected and all was good