Mysterious unsolvable Yamaha double-striking uprights

Paul McCloud pmc033@earthlink.net
Tue, 12 Jul 2005 05:51:43 -0700


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Just a thought... If the tip of the jack is squared at 90 degrees, the forward edge (closer to the strings) will tend to give the butt a little kick as it's getting away from the butt.  Examine the tip of the jack(s) and see if they are angled at the tip. You might even file a little off and see if it helps.  FWIW.
Paul McCloud
San Diego





----- Original Message ----- 
From: Stéphane Collin 
To: Pianotech
Sent: 07/12/2005 9:11:13 AM 
Subject: Re: Mysterious unsolvable Yamaha double-striking uprights


Hello Geoffrey.

What could possibly cause the hammer to hit the string before letoff has occured ?  Maybe the centers are too far away from the strings, and the hammers don't strike at a right angle, so gravity causes the hammers to move away from the jack ?  I can't see what other force could cause this premature movement.

Best regards,

Stéphane Collin.

What I am witnessing is this: When I play the note, just before the jack releases from under the butt the hammer jumps off the jack prematurely and strikes the string. After striking the string the hammer then bounces back onto the jack, which is still in it's pre-release position. Continuing through the keystroke results in the hammer striking the note a second time as the jack finally releases from under the butt. 
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