I have a 1980's KM-850 Bought on Ebay.Fantastic wood & workmanship-almost mint-which brings me to the problem.I think it has hardly been played & has been kept in it's case unplayed for months or years.So the neck has a kink at the 12th fret-straight from nut to 12-I'VE TIGHTENED THE TRUSS ROD,but it's still the same.Perfectly playable,but the fingerboard extension means pick clicking.I know I could get the frets filed down or even removed,but my main concern is that the mandolin just doesn't produce the tone or volume it should.Ideas please!