I am getting thermal runaway even after PID autotunning many times. I tried 10, 15, 20, 25 and 30 cycles and after reuploading FW onto the printer but I still get the error...
I've built a copy of Prusa's i3 mk2 by following Building the cheapest possible Prusa i3 MK2.
I have tried autotune with the cooling fan off, 50 %, and 100 %, but nothing changes.
The printer is in a closed cabinet room.
I was just watching it printing + temperature graph, and after ~20-30 minutes it starts jumping from 199.3-5 to 200.6-9... And that causes, after a few minutes, thermal runaway. The fan was on for 15 minutes or more.