<HEAD> <META content="MSHTML 6.00.2900.2963" name=GENERATOR></HEAD> <BODY> <DIV>Mark-</DIV> <DIV>See if the jack is just a little slow to return when it has been held in extreme let-off position for a moment.</DIV> <DIV>See if the hammer cushion on the wippen is low.</DIV> <DIV>Ed Sutton<BR><BR><BR></DIV> <BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 0px; BORDER-LEFT: #0000ff 2px solid">-----Original Message----- <BR>From: Mark Potter <BASES-LOADED76@SBCGLOBAL.NET><BR>Sent: Sep 25, 2006 12:08 PM <BR>To: Pianotech List <PIANOTECH@PTG.ORG><BR>Subject: action reg puzzler on M & H BB <BR><BR> <DIV>List -</DIV> <DIV> </DIV> <DIV>I am having a puzzling problem with a M & H BB grand action that I have never encountered.  Complete regulation (w/new shanks& hammers), everything works great with the exception of 3 notes - F6, A#6, G7 -  in the high treble.  I cannot get this to happen on the bench, and even in the piano when the notes are played softly, even in a trill, they perform perfectly.  However, under continuous mf - ff blows, as in tuning, after anywhere from 1 to 10 strikes (letting the key all the way up), the hammer will get caught on it's way back up by the back check, thereby not allowing it to strike.</DIV> <DIV> </DIV> <DIV>I have tried numerous adjustments to the angle of the back check as well as to the height of check for these 3 notes, to no avail.  Everything seems to be identical to the surrounding notes, including jack reg - both in the window and to the knuckle core -, rep spring strength, key dip, stroke, the arc of the tails, let-off, drop, etc., etc... you name it.  Keys are rebushed and moving freely.</DIV> <DIV> </DIV> <DIV>If anyone can shed some light on this puzzler I would be most grateful!!</DIV> <DIV> </DIV> <DIV>Mark Potter  </DIV></BLOCKQUOTE></BODY>