I just swapped out my MicroSwiss direct-drive extruder and hotend for a Creality Sprite Pro on my Ender 3 with an upgraded mother board to the BigTreeTech Octopus v1.1 and I'm experiencing thermal runaway on power-on.
Previous (working) configuration:
- Ender 3 pro
- BigTreeTech Octopus v1.1 loaded with Klipper firmware
- MicroSwiss direct-drive
- Ender 3 pro
- BigTreeTech Octopus v1.1 loaded with klipper firmware
- Creality Sprite Pro
Steps that I'm taking to hit thermal runaway:
- Turn on power switch for the Ender 3 Pro.
NOTE: Thermal Runaway Protection does not work here. The TRP detects and triggers, but Klipper doesn't seem to have any ability to control the heating tube. Instead, Klipper shuts down and the heating tube keeps running away. Each time I've had to cut the power manually.
Additional things that I've tried:
- Powering on using the power from the Raspberry Pi's USB port - this powers on the printer but will error on any attempt to drive motors or run the extruder. RESULT: thermal runaway to the best that it can, plateauing around 60 °C.
- Powering on using the power from the Raspberry Pi's USB port, then disconnecting and powering on without the Raspberry Pi connected, then powering down and reconnecting the Raspberry Pi - this confirms for me that in the absence of the Raspberry Pi, it still reaches a runaway state; RESULT: monitoring before and after powering manually showed a jump of 100 °C in 30 seconds, meaning if the printer has power, it will power the heating tube with as much as it can.
- Reversing the + and - wires - this is the recommendation in the instruction manual, "If 3D printer restarts during hotend heating up, please reverse the heating tube connectors on mainboard"; RESULT: prevents the printer from powering on - everything appears dead and returning the cables to the correct polarities returns it to a runaway state.