Hi and welcome to the site, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, a little more background info please:
Appreciate the additional information.
Are you then considering a DIY (do-it-yourself) repair approach? If yes, it may need to have access to and familiar with a multi-meter.
more importantly, would be be comfortable "working under the hood" ?
Great on the DIY!
Gain access to the motor area. Take clear pictures of the motor controller and the motor itself. Of particular interest would be the motor pulleys and ends. Also of the roller closest to the motor.
Post back thses pictures. Please click HERE.
The motor can be tested with a 12V car battery.
The controller's output voltage can be checked for its presence and consistency as supplied to the motor.
The speed sensor can be checked / adjusted.
Appreciate the post back and an update when able.
Good luck and thank you for the opportunity to share the information.