Extruder and Y-axis motors getting very hot, even unused extruder

Sovol SV02
1

Hello everyone,

I’m having an issue with my Sovol SV02 where the motors are getting excessively hot.

Symptoms:

  • The left extruder motor (E0) gets very hot (approx. 77°C measured with an IR thermometer) after just one hour of printing.

  • The right extruder motor (E1) also gets warm (approx. 65°C), even though it was not used during the print.

  • The Y-axis (bed) motor also gets warm (approx. 57°C).

  • In contrast, the X-axis motor remains cool at 38°C.

  • The hotend heatsink and the Bowden tube fittings are cool, so heat creep from the hotend itself seems unlikely.

My setup:

  • The printer has the original Creality V2.2.1 mainboard with an Atmega 2560 chip.

  • It is running Klipper, installed on a Dell ThinClient.

Troubleshooting steps I’ve already taken:

  • Replaced the nozzle, including the heatbreak and heatblock.

  • Replaced the hotend fan and the fan shroud with a new one that has better physical isolation between the heatblock and the heatsink.

  • Adjusted the potentiometers on the mainboard for E0 and E1 down to 0.5V.

  • Added a second, large fan pointing directly at the mainboard from above, in addition to the original board fan.

  • Completely reverted the printer.cfg to the original, first-known-working version.

  • Reduced retraction to 1mm at 10mm/s.

  • Completely disabled Pressure Advance.

Despite all this, the motors, especially the extruders, are still running too hot. Does anyone have an idea what could be causing this, especially the heating of the unused right extruder motor? Any help would be greatly appreciated.

2

The “hold current” will still heat a “unused” stepper motor.

Without a UART enabled mainboard I know of no way under klipper to change the currents.

The simple fix is a more modern mainboard.

Someone at General Discussion - Klipper might be able to help.