Bad Thermistor Symptoms 3d Printer

Dec 15, 2017 – I always find it interesting that 3D printers — at least the kind most of us. too much current through the thermistor because that current causes.
The failure mode is that the temperature abruptly changes for several seconds, then flips to another value. I suspect it is thermal stress in the thermistor which is changing the value. When the hotend reaches a stable temp, the temp reading also stabilises. I will also take a look at the signal with the scope.
So i decided to go buy a Infrared thermometer to check the temp of the extruder to see if it was possibly getting hotter than the readout on my printer is saying.
It went all bad, the temp wasn’t stable anymore and I thought it was the Thermistor or the Heating element of.
The main problem appears to be that the extruder is not heating to what it says it is which causes the filament to heat slowly and then clog easily. When the screen reads 260ºC, it can barely melt PLA. If the thermistor was broken, then I feel it would not read temperature at all.
When temperature increases, the resistance increases, and when temperature decreases, I’d highly recommend this kit to anyone interested in 3D printing.
Nov 30, 2016 – I replaced the filament spool, reset the printer (it also had a “thermal. Needless to say the part was looking pretty bad: layer separation & lots of. From my understanding these are clear signs of under-extrusion. Never mind, just read the section in the 3D Printing Handbook .