<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META content="text/html; charset=iso-8859-1" = http-equiv=Content-Type> <META content="MSHTML 5.00.2614.3500" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face=Arial>Dave , Just a guess, but from your description = and careful inspection , I'd suspect a sudden change between the pinblock and the = plate flange. Perhaps some type of glue joint failure ,especially if the block = is in sections.That hitch pin area does seem suspicious, but  if the = plate was broken or had a crack, it would seem to me that tuning stability would = not be possible at any pitch. I'm thinking that any failure in that block, = back post, fillers etc assembly would be loud,and create the changes as you = describe. Maybe the plate flange is what cracked? Late night speculations from a cold = Northeast .  Tom Driscoll</FONT></DIV></BODY></HTML>