The museum where I volunteer has a player piano, which had the player
action restored by a novice about ten years ago.  Still, it does
remarkably well.  However, recently it has had difficulty maintaining
an even tempo.  But this problem is not consistent. Sometimes it is
okay, sometimes not.

We have had an unusually damp winter/spring here (in North Texas),
and, about two years ago our air conditioner went out and the piano sat
in an un-climate controlled environment (never exposed to the elements,
just no heat or AC) for about a year and a half.  Can anyone suggest
what the cause of the problem might be?

Bryan S. Cather