Hi, this is Jean-Luc and I'm back with my key height hypothesis. Here is a possible scenario: sometime in a recent past a technician noticed the bobbling hammers and saw there was a lot of lost motion. He concluded that was the problem because that is often the case so he raised the capstans. It helped a little but not quite enough so he raised them a little more and now the butts are riding on the jacks. It helped a little more but not completely and now the jacks do not escape, it feels that there is no let off. You adjust the let off way early now it kind of works but feels weird because the jacks are still too high. So I'm back with my idea, try it on one key see if it works: lower the capstan, add some paper punching to raise the key a little and reajust your let-off and lost motion. I never contribute to this list but I really think I'm on to something this time. Good luck JL In a message dated 1/23/2009 5:24:05 P.M. Mountain Standard Time, koko99 at shaw.ca writes: I tune many Yamaha teaching pianos in our town, and almost all the new Yamahas exibited similar traits described herein. First time tuning these new pianos, I did some let-off adjusting. Next time tuning , (3 months), same problem was there, although I don't know if the same keys were at fault, cause I really didn't take note the first time, thinking that problem should be solved. I just take a large screwdriver and bear up on the letoff rail, and this usually tells me that that's the problem. Other times , I've adjusted the capstans up to make for less lost motion. This worked, too. Soooo, sounds like the previous writer says that it probably needs more than one adjustment, but several. Think he's right. I would like to know , if in fact, there is a definitive answer . ( springs ?? ) Carl / Winnipeg ----- Original Message ----- From: _Ryan Sowers_ (mailto:tunerryan at gmail.com) To: _pianotech at ptg.org_ (mailto:pianotech at ptg.org) Sent: Thursday, January 22, 2009 5:49 PM Subject: Re: [pianotech] Bobbling hammers and jack spring pressure? My vote is for the damper springs. They are often set much stronger than they need to be and do cause some resistance to a full key stroke during gentile playing. I ran into a similar problem a while back and a compromise between a little extra let-off, a tiny bit more key-dip, a weaker damper spring, and timing just a wee bit later. Sometimes you can combine several subtle adjustments to get the result your looking for. Ultimately I believe this may be a geometry issue that these pianos might have. I was recently having a conversation with Ed McMorrow about this and he claimed it had something to do with the relations of the action centers and over centering of the hammer. We hear so much about grand action geometry but not enough about upright geometry. On Wed, Jan 21, 2009 at 8:22 AM, Gregor _ <_karlkaputt at hotmail.com_ (mailto:karlkaputt at hotmail.com) > wrote: List, is there a way to ease the jack spring? I have problems with a Yamaha P121N upright that has bobbling hammers. The hammer butt is dancing on the jack tip. All regulation measures are okay and there is enough aftertouch. I suspect the jack spring being too strong. Any thoughts how to get it right? There is no lost motion, check is about 15 mm, aftertouch is okay and I gave some talkum powder to the jack tip and the let off button. The only thing that helped was to set the let off to 10 mm, but that´s not a satisfying solution. The strange thing is that one could play without bobbling hammers but something makes the player stop pressing down the key before the let off point. A very subtile resistance gives the player a hint that the key is pressed down now, but that´s not right. The player could and should press further on. The strange thing is that this problem is new for a few days. I should mention that we had very dry air last weeks and the customer has a floor heating. Therefore I suspect a connection between this problem and the dry air. Any comments? Gregor ____________________________________ What can you do with the new Windows Live? _Find out_ (http://www.microsoft.com/windows/windowslive/default.aspx) -- Ryan Sowers, RPT Puget Sound Chapter Olympia, WA _www.pianova.net_ (http://www.pianova.net/) **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! (http://pr.atwola.com/promoclk/100000075x1215855013x1201028747/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072%26hmpgID=62%26bcd=De cemailfooterNO62) -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090124/200cf1a3/attachment-0001.html>
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