Annoying buzz

[Sevas Tra]

I have a loud buzz every time i play open A or the A an octave above that. I've messed around and i think it's coming from the peg for my D string (not exactly sure how that works) and it's starting to annoy me. Any possible ideas for fixing it? I think that the end of the peg is loose or something but i'm not completely sure.

[Jake deVilliers]

The 'D' string peg is the one that gets hit the most going through doorways and into cars etcetera and the tuner 'button' can be knocked loose. If you tap the button lightly with your fingers you'll hear it click.

I usually remove the offending plate and re-solder the button to the shaft to make it quiet again.