Hi, I have a 1997 Rickenbacker 4003 and I am noticing some fret buzz in a couple different places. This doesn't happen when only one note is being held down, but rather when I am holding down another note at the same time (not necessarily sounding the note even.) I'm almost certain it isn't my strings or the action, so I was thinking maybe my frets need to be looked at. The only problem is I don't know anything about fret care or replacement or anything. Is this something I should even be looking at or is there something else going on? How much should it generally cost for someone to do something to the frets? Any help or insight is greatly appreciated.