The Dino should move left to right during play, unless this is disabled in the settings. There is a "home" switch, which is in alignment with the hole that the Dino picks the ball out of. So for the Dino to either move up or down, this switch must be on.

Up and Down - Set of switches can can go out of adjustment. The Dino should slow down as it lowers and then the mouth fully opens. It snaps closed when the "down" switch is closed, and then heads back up. More than likely, it will be a loose wire(s) or a broken "down" switch. It SHOULD be an easy fix, and it could also be the "up" motor.

There is a relay that operates the Dino that ALWAYS has cold joints. Could be as simply as this.