On Sun, 25 Apr 2010 14:00:42 -0400, jeff_wisnia
wrote:

terry wrote:

....


If it does have a magnetic ballast, and tightening the ballast mounting
doesn't work you could try what an office maintenance worker "tought me"
a long time ago.

Dismount the ballast, hold it in one hand and give it a couple of whaps
on its side with the ball end of as BP hammer. Make some minor dents to
tighten the case against the ballast lamination stack.

Jeff
....

Or replace it with a modern electronic ballast.