There is something off with the Bed Temperaure but it's not the Thermistor

Ahrimaan — Fri, 01 Aug 2025 17:15:14 +0000

Heya lovely People,

i have over 80 H printed on the Core one and now got a weird error:
When i print something, the Heatbed starts to drop (120C to 114C) and then the Printer goes into Thermal Runaway.
When i print with 110C Degree, it drops too but not that fast until 103. Then after xx minutes of Printing it starts getting higher again.
I checked the GCode , nothing unusual
When i leave the printer idle and just put the heatbed manually to 120C it stays there for Hours.

I tried to wooble the cable, all good.
My assumption is, it is not the Thermistor as the Bed recovers. It seems like the inner resitance in the heatbed gets too high and the board is not able to pump in enough energy so it drops.

Any other ideas ?

There is something off with the Bed Temperaure but it's not the Thermistor - Hardware, firmware and software help

There is something off with the Bed Temperaure but it's not the Thermistor