Capping station motor shaking on Teleios 180tx with RIPSTAR mainboard

[maximumapogee]

I have a Teleios 180tx textile printer with a RIPSTAR 1.7.2 mainboard. The motor that raises and lowers the capping station will intermittently shake while turning, usually after 10 or 20 minutes of inactivity. I've tried swapping the capping station motor with the wiper motor and the problem stays with the capping station motor. Any one have have any ideas what's causing it? I can see 2 potentiometer on the mainboard where the motors plug into it, but I don't know what they do. Anyone have any documentation for the RIPSTAR 1.7.2 mainboard?

Video of shaking: https://drive.google.com/open?id=1-4RwOOaG-M8CfdIx_GbcCPqPKHeaJzuY