I forgot to mention that when you regulate the balancier height do so by rolling the jack tender and the top of the jack should just barely brush the knuckle but should not be inhibited in any way from returning to its rest position. Be sure that the repetition spring is regulated to the correct tension before you do that. David Love www.davidlovepianos.com -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of David Love Sent: Sunday, February 14, 2010 4:39 PM To: pianotech at ptg.org Subject: Re: [pianotech] More on Yamaha Sticking C6 Key Problem It certainly seems from your description that the jack center could be a bit tight. You should be able to tell by rolling it and releasing it comparing it with others around it. Try lubricating with some Protek. That often helps on Yamaha centers that tend to develop excess friction periodically for some reason. While you're at it lubricate the hammer flange centers and the wippen centers. Also, it could be that the balancier is regulated too low combined (perhaps) with a weak repetition spring. If the jack protrudes to far above the balancier it will be inhibited from getting back under the knuckle. Increase the tension on the rep spring so that you get a very positive rise. The speed should be similar to how fast your arm would move to toss a tennis ball about 18 inches in the air (one way to think about it). Also, be sure that the jack is aligned correctly with the back of the knuckle core. If you think the damper may be influencing things check the repletion with the damper pedal engaged. David Love www.davidlovepianos.com -----Original Message----- From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of rsfinley at charter.net Sent: Sunday, February 14, 2010 2:53 PM To: pianotech at ptg.org Subject: [pianotech] More on Yamaha Sticking C6 Key Problem Here are some more observations on the intermittent problem with the C6 on my Yamaha G1 Piano. When I play the key the first time, the note usually sounds, but if I play repeatedly and quickly after that, it stops sounding. I have to wait a few seconds after that for the key to recover, before it will play again. It seems there is a delay of a few seconds when part of the action is slowly getting back into the position when the key can be played. I am puzzled why there is this delay. When I take the action out and put it on a table, I cannot reproduce the sticking key effect for C6, even if I simulate the presence of the string using a hard book held some distance above the hammer (of course the hammer will not rebound in the same way as for a string). I can cause the hammer to move in fast repetition without any blocking effect. The sticking key effect only occurs when the action is back in the piano. Although I doubt it, I am wondering if this is a combined effect of the damper and the action causing this sluggish operation, although the damper for C6 seems to be working fine. When I look at action for C6 (difficult to see everything due to the proximity of the actions of the other keys, everything appears to be intact. I haven't removed the whippen assembly for C6 yet to examine it in detail. Maybe I should do that. Could anyone throw more light on this? Thanks for your advice. Robert
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