This just happened to me and I'm baffled. I was finally getting my dome to operate correctly when I was slewing the dome, and it didn't move, I was watching through my dome camera. I sent it home and could hear the motor turning, but the dome didn't move. When I went out, the tension bolt was loose and the gear was disengaged from the track. I quickly tightened it back up, but it shouldn't have come loose. When I find my Loctite I'll fix it permanently, but wow.
Anyone had this problem? If not, check your installation if using the newer rotator motor attachment, see photo.