I bought my JTV-89 on Ebay. I knew that there would be a gamble with it to a degree but have been VERY happy other then one small issue. When I received the guitar, the Alternate Tuning nob is loose, as in it moves more freely than it should. The nob works just fine and there is no issue adjusting between tunings it's just loose in the seating. I have tried to figure out how to tighten it but with the electronics, I don't want to screw something up. Does anyone have any ideas as to how this could have happened or what I can do to correct it?