I just recently bought a 1976 Fender Musicmaster that is in near perfect shape and was working the first week i had it. Now everytime i try to record it it sounds muddy and dull. I recorded with it the first week i had it and it sounded great, it was punchy and clear with a good amount of high end. Now it just sounds like i turned all the high end off and put distortion on it. What could be the problem? And how much would it be to get something like this fixed? It seems as though the tone knob just stopped working.