I have a very weird problem where the print always fails on the same spot due to thermal runnaway(???) The temperature curve in the picture was exactly the same all 3 times i tried the print. Any idea what might be causing this?
37C seems REALLY hot for something that’s supposed to be off. do you have cooling on the control board at all?
Что происходит в момент снижения температуры? Включается обдув детали?
У меня было такое, когда включались вентиляторы. Системе не получалось вернуть температуру на нормальную и прошивка выключала питание.
Мне помогло утепление греющего блока фторопластовой лентой.
@Tom_L It’s chambered
aaah, it’s probably because i removed the E3D silicone sock from the hotend. It happens on the 1st top solid layer where the bridge cooling gets enabled. 
Thanks to @Pavel_Omelchenko . I don’t know if this was what you ment because i had to translate your text but thanks anyway
okay, I guess that makes sense about the temp, but do you have the control board cooled at all?
If you using marlin firmware, look at this
https://github.com/MarlinFirmware/Marlin/blob/RC/Marlin/Configuration_adv.h#L76
sorry for my previous comment, my english so bad =)
@Tom_L Yes. It’s on the outside of the machine and cooled with a 60x60 fan.
You might need to replace the thermistor. I have had this happen and the printer printed just fine then it said error max temp, replaced it and it worked just fine, Hope it helps.
Might need to adjust hysteresis settings in configuration_adv.h