MK3S is no longer able to maintain hotend temp
I got my MK3S in May of 2019. It's been working great until last night. I successfully printed a couple things in prusament PETG, then I switched to PLA and all of a sudden something is wrong. Now, when the cooling fan comes on, the hotend temperature drops and never recovers. I'm printing prusament PLA at 215C. When the fan comes on, it drops to 205 and never recovers. Then I get the THERMAL RUNAWAY warning and the print stops. Can anyone help me out with this?
RE: MK3S is no longer able to maintain hotend temp
I got my MK3S in May of 2019. It's been working great until last night. I successfully printed a couple things in prusament PETG, then I switched to PLA and all of a sudden something is wrong. Now, when the cooling fan comes on, the hotend temperature drops and never recovers. I'm printing prusament PLA at 215C. When the fan comes on, it drops to 205 and never recovers. Then I get the THERMAL RUNAWAY warning and the print stops. Can anyone help me out with this?
I would first check the thermistor (resistance 100) and the wires. A typical problem if thermal runaway occurs.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: MK3S is no longer able to maintain hotend temp
While printing with PETG you should also reduce the fanspeed to 35%. Maybe you try this first.
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: MK3S is no longer able to maintain hotend temp
@karl-herbert
I'll try that the next time I go to print PETG. It's currently failing to print PLA. It used to print PLA fine with the fan a 100%.
I'll work on measuring the resistance of the thermistor.
RE: MK3S is no longer able to maintain hotend temp
@karl-herbert
I measured the resistance of the thermistor. It came back at 118kOhms, which is consistent with what should be expected according to the Prusa site. So I suppose this means the measurement is correct and the hotend is indeed unable to maintain the proper temperature.
RE: MK3S is no longer able to maintain hotend temp
Last one of these I saw I think the heater wire had a bad connection to the Einsy board. Broken wire or bad connector...
RE: MK3S is no longer able to maintain hotend temp
Connection to the Einsy board looks fine. I tried tightening up the terminal blocks just in case. I also ran the PID calibration. Still having the same issue. I set the fan speed to 75% and that was enough to keep the temperature over 200 and avoid triggering the thermal runaway. This isn't really a solution though. I'm thinking my heater is no good.