What is the problem?
Nach einem Update der Firmware auf Knutwurst Marlin MEGA_v1.5.4.hex erhalte ich plötzlich Thermal runaway Fehler.
Send: M106 E0 S191
Recv: ok
Send: M105
Recv: ok T:131.13 /0.00 B:26.79 /0.00 @:0 B@:0
Send: M105
Recv: ok T:126.84 /0.00 B:26.79 /0.00 @:0 B@:0
Send: M303 E0 S230 C5
Recv: //action:notification PID Autotune
Recv: PID Autotune start
Recv: //action:notification Heating...
Recv: T:122.78 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:121.34 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:120.74 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:121.39 /0.00 B:26.59 /0.00 @:127 B@:0
Recv: T:123.23 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:126.42 /0.00 B:26.73 /0.00 @:127 B@:0
Recv: T:130.13 /0.00 B:26.59 /0.00 @:127 B@:0
Recv: T:134.44 /0.00 B:26.65 /0.00 @:127 B@:0
Recv: T:139.30 /0.00 B:26.62 /0.00 @:127 B@:0
Recv: T:144.33 /0.00 B:26.68 /0.00 @:127 B@:0
Recv: T:149.96 /0.00 B:26.62 /0.00 @:127 B@:0
Recv: T:155.28 /0.00 B:26.65 /0.00 @:127 B@:0
Recv: T:160.67 /0.00 B:26.59 /0.00 @:127 B@:0
Recv: T:166.08 /0.00 B:26.65 /0.00 @:127 B@:0
Recv: T:171.39 /0.00 B:26.68 /0.00 @:127 B@:0
Recv: T:177.19 /0.00 B:26.73 /0.00 @:127 B@:0
Recv: T:182.52 /0.00 B:26.68 /0.00 @:127 B@:0
Recv: T:188.05 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:193.49 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:198.61 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:203.89 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:208.01 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:210.63 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:211.25 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:211.68 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:210.66 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:209.57 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:207.62 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:205.63 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:203.33 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:201.08 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:198.64 /0.00 B:26.73 /0.00 @:127 B@:0
Recv: T:196.42 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:194.09 /0.00 B:26.85 /0.00 @:127 B@:0
Recv: T:191.36 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:188.75 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:185.91 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:183.46 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:180.79 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: Error:Heating failed, system stopped! Heater_ID: E0
Recv:
Changing monitoring state from "Operational" to "Error"
Send: M112
Send: N3 M11234
Send: N4 M104 T0 S037
Send: N5 M140 S0*96
Changing monitoring state from "Error" to "Offline after error"
Connection closed, closing down monitor
What did you already try to solve it?
Ich habe:
Verschiedene Hotends, verschiedene Thermalsensoren und Hitzepatronen und unterschiedliche Lüfter getestet.
PID mit und ohne Lüfter
Downgrad auf die letzte Anycubi Firmware
Rückkehr zur "Knutware"
PID, verschiedene Benchydrucke
Extrusion eingestellt
Steps aktualisiert
Mit Pronterface und Cura ohne Octoprint getestet
Immer das gleiche Problem: Erst wird stabile geheizt, und nach einer gewissen Zeit oder im 2. oder 3. Zyklus bricht plötzlich die Temperatur ab bzw. es scheint, als ginge die Heizung aus. Nach einer Neuverbindung kann man aber direkt wieder starten.
Have you tried running in safe mode?
nein, da es offensichtlich kein Octoprintproblem zu sein scheint.
Did running in safe mode solve the problem?
siehe oben
Systeminfo Bundle
octoprint-systeminfo-20250429145830.zip (270.3 KB)
WRITE HERE
Additional information about your setup
OctoPrint version 1.11.0, OctoPi version Raspi 3B, Anycubic i3 MEGA, MEGA_v1.5.4, Chrome, Windows 11
Danke an alle 
Hello @der_Arndt !
Please use English language.
I´m pretty sure every Browser supports direct translation but anyhow

What is the problem?
After updating the firmware to Knutwurst Marlin MEGA_v1.5.4.hex I suddenly get Thermal runaway error.
Send: M106 E0 S191
Recv: ok
Send: M105
Recv: ok T:131.13 /0.00 B:26.79 /0.00 @:0 B@:0
Send: M105
Recv: ok T:126.84 /0.00 B:26.79 /0.00 @:0 B@:0
Send: M303 E0 S230 C5
Recv: //action:notification PID Autotune
Recv: PID Autotune start
Recv: //action:notification Heating...
Recv: T:122.78 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:121.34 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:120.74 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:121.39 /0.00 B:26.59 /0.00 @:127 B@:0
Recv: T:123.23 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:126.42 /0.00 B:26.73 /0.00 @:127 B@:0
Recv: T:130.13 /0.00 B:26.59 /0.00 @:127 B@:0
Recv: T:134.44 /0.00 B:26.65 /0.00 @:127 B@:0
Recv: T:139.30 /0.00 B:26.62 /0.00 @:127 B@:0
Recv: T:144.33 /0.00 B:26.68 /0.00 @:127 B@:0
Recv: T:149.96 /0.00 B:26.62 /0.00 @:127 B@:0
Recv: T:155.28 /0.00 B:26.65 /0.00 @:127 B@:0
Recv: T:160.67 /0.00 B:26.59 /0.00 @:127 B@:0
Recv: T:166.08 /0.00 B:26.65 /0.00 @:127 B@:0
Recv: T:171.39 /0.00 B:26.68 /0.00 @:127 B@:0
Recv: T:177.19 /0.00 B:26.73 /0.00 @:127 B@:0
Recv: T:182.52 /0.00 B:26.68 /0.00 @:127 B@:0
Recv: T:188.05 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:193.49 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:198.61 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:203.89 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:208.01 /0.00 B:26.70 /0.00 @:127 B@:0
Recv: T:210.63 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:211.25 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:211.68 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:210.66 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:209.57 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:207.62 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:205.63 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:203.33 /0.00 B:26.76 /0.00 @:127 B@:0
Recv: T:201.08 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:198.64 /0.00 B:26.73 /0.00 @:127 B@:0
Recv: T:196.42 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:194.09 /0.00 B:26.85 /0.00 @:127 B@:0
Recv: T:191.36 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:188.75 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:185.91 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: T:183.46 /0.00 B:26.82 /0.00 @:127 B@:0
Recv: T:180.79 /0.00 B:26.79 /0.00 @:127 B@:0
Recv: Error:Heating failed, system stopped! Heater_ID: E0
Recv:
Changing monitoring state from ‘Operational’ to ‘Error’
Send: M112
Send: N3 M11234
Send: N4 M104 T0 S037
Send: N5 M140 S0*96
Changing monitoring state from ‘Error’ to ‘Offline after error’
Connection closed, closing down monitor
What did you already try to solve it?
I have:
Tested different hotends, different thermal sensors and heat cartridges and different fans.
PID with and without fan
Downgraded to the latest Anycubi firmware
Return to the ‘Knutware’
PID, various benchmark prints
Extrusion set
Steps updated
Tested with Pronterface and Cura without Octoprint
Always the same problem: first the heating is stable, and after a certain time or in the 2nd or 3rd cycle the temperature suddenly drops or it seems as if the heating goes out. After a reconnection, however, you can start again straight away.
Have you tried running in safe mode?
No, as it does not appear to be an Octoprint problem.
Did running in safe mode solve the problem?
see above
Systeminfo Bundle
octoprint-systeminfo-20250429145830.zip (270.3 KB)
WRITE HERE
Additional information about your setup
OctoPrint version 1.11.0, OctoPi version Raspi 3B, Anycubic i3 MEGA, MEGA_v1.5.4, Chrome, Windows 11
Thanks to all 
Translated with DeepL.com (free version)
Does it also happen when you heat just the bed?
No, the Bed works without any issues up to 100 degrees.
Ich bin auf ein ähnliches Problem gestoßen. Überprüfen Sie Ihren Hotend-Sensor.
Wie schon geschrieben tritt das Problem mit verschiedenen Sensoren auf. Ich habe originale und Zubehörteile versucht.
& @der_Arndt :
Please stick to English language!