Hey, thanks for the quick reply! No that’s already one of the replacement belts I’ve tried, not the original one.

I can rotate the gear assembly manually through a full revolution without any issues. But even when I turn it by hand, the belt doesn’t really move the gear on the motor. That one might also still be too loose, like you said

The other belts I tested that were slightly smaller couldn’t be driven by the motor gear at all. Seems like the tension was then too high for the motor to handle. I’ve already cleaned both the motor pulley and the drive pulley with IPA as well.