One of my clamps on my alpha pioneer DC plus could use some tightening up. To lock the base, I have to turn the lever way to the other side. I would like to tighten it so I can lock and tighten the base easier. Does anyone know how this is done? the manual said to insert an alan wrench into a hole in the base and tighten, but I tried that and 1. It didn't seem to be entering into a socket for an alan wrench, so it was having no effect and 2. I wasn't sure if that was actually the method for making the locking mechanism tighter.