Wobble screw in site
OK. Lower left. See that hole? It leads all the way down to one of the screws holding this whole thing together. You may need to actuate the tilt mechanism to get all the way down there. I believe that it's a 6mm reverse torx (female torx). Unscrew (if still screwed in) the screw. Coat the screw with Locktite 271 or equivalent anti-vibrate locktite and screw it back in as tight as you can get it!.