I just got a Cobra a couple of days ago. I really like it but there is one problem with it. It seems that the top nut is only hanging on by one thread. With thicker gauge wirer I have a very hard time getting the top nut to tighten all the way....half the time it just falls off. I have completely tightened the unit by holding the bottom nut with pliers and tightening the positive post with a screwdriver. Anyone had similar problems? Any suggestions?