action reg puzzler on M & H BB

David Chadwick chadwick61 at cox.net
Mon Sep 25 18:49:30 MDT 2006


Mark, 
This maybe obvious but no one has mentioned it so for is to see if the hammer is supported off of the hammer rest support felt by turning the capstan up. The rapid key motion should be in route and in unison with the stack action components otherwise the back check is making contact with the hammers shoulder and pinching it down. You also might check the repetition spring and regulate it slightly stronger. 

David 
Las Vegas
  ----- Original Message ----- 
  From: Mark Potter 
  To: Pianotech List 
  Sent: Monday, September 25, 2006 3:55 PM
  Subject: Re: action reg puzzler on M & H BB


  List -

  The many suggestions for this problem are greatly appreciated!  I just got back in and plan to sneak in an hour or so in the shop tonite to pursue some of these suggestions.  I can say outright that pulley keys are not the problem, nor is the backcheck loose in the key, and they are certainly good suggestions, but ones I had already ruled out.  The aftertouch is even thruout, and only these 3 keys act up, so I don't know about that either, although I will certainly mess with it. The jack is properly set in the window to just kiss the knuckle at rest (and I did introduce some lost motion in the process of tracking this down, but it didn't help), and there is no sign whatsoever of sluggishness from the jack that I can detect on the bench.  The best I can tell in the piano, even when the key jams (hammer caught on the backcheck on its way up) the jack does seem to be under the knuckle and trying to push it up.  I like Ed F's suggestion to change out a wippen to aid in the diagnosis, and Ed S's suggestion to add a bit of felt to the rest cushion.  I never thought to check the way the spring interacts with the insertion point of the jack, since the jack doesn't SEEM to bind.  I'll check it now, though.  Small steps for mankind...

  I will report any progress or lack thereof.  Thanks again for the suggestions!

  Mark Potter  
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