My sister plays a vintage Deagan marimba. In May of 2010 she had it tuned by Master marimba tuner Gilberto Serna. Here is a little video from when we dropped it off and then came back a week later to pick it up. Just click on the words Deagan Marimba above.
Mr. Serna still tunes and repairs marimbas at the old Deagan building in Chicago. Here is a great history of: Deagan Marimbas.