have a 2020 big country 3902FL. All slides closed and opened prior to this trip. Closed slides to depart, upon arrival and setting up, the other half was opening slides and discovered living room slide was cocked. Forward side, of slide did not move, although the aft side did. Tried opening and closing, nothing worked, finally by pushing on the forward side and bumping the controller to keep even, almost open fully, so we could function. I could hear motors running, but slide not operating. Had a mobile tech come out and found a set screw loose, so motor would run, but drive shaft didn't move, tightened up and ops checked working as advertised.