[font="helvetica, arial, sans-serif"][color="#282828"]I have a S.U.B. STERLING RAY 4 by Musicman and one of the knobs (the treble) the knob has become loose and does not turn aswell. The control is very loose but working. Nothing out of ordinary happened, just noticed it the other day. Can I fix it? If so, how? Can a shop or guitar shop? [/color][/font]