Paul, I jumped in when I saw that Gregor mentionned dry air. I'm not saying that all cases of boobling hammers are due to a drying and sinking kebed but I can testify, after working several years for a local dealer, that a lot of new Yamahas uprights would be fine upon arrival but start getting bobbling hammers after a couple of months on the floor. The only way to fix that problem was to raise the key height one way or another. I don't know whether it was the keybed, the punchings, the keys themselves, but the key height had become too low and the regulation was gone. Jean-Luc In a message dated 1/22/2009 12:03:25 A.M. Mountain Standard Time, PAULREVENKOJONES at aol.com writes: Jean-Luc: Realize that what you are doing is increasing aftertouch (by raising the overall key height at the balance rail) which is the distance the jack travels after escapement. The bobbling in this instance is caused by zero or negative aftertouch, and the hammer butt is bouncing off the jack top (which is not escaping) and "bobbling". I find it hard to believe that "new pianos" suffer a general defect like this simply because of low humidity. Paul In a message dated 1/22/2009 12:22:12 A.M. Central Standard Time, Jlmatt at aol.com writes: We have to deal with bobbling hammers in new pianos quite often after they arrive here in the dry climate of New Mexico. but the jack spring has nothing to do with it. Raising the balance rail usually takes care of that problem. Try it on one key, raise it with a couple of paper punchings, and reajust the lost motion, and if that helps, then you can do it on all the keys quickly by shimming the balance rail with a a few business cards or something Good luck Jean-Luc In a message dated 1/21/2009 9:23:36 A.M. Mountain Standard Time, karlkaputt at hotmail.com writes: 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) = ____________________________________ 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&hmpgID=62&bcd=DecemailfooterNO 62) ____________________________________ 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&hmpgID=62&bcd=DecemailfooterNO 62) **************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/20090122/e0c88e0c/attachment.html>
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