Hi all: I tune a LOT of new Yamaha uprights, and they all do this to some extent. You have to check two things: the lost motion-as soon as there is more than enough,the problem will occur; and you have to weaken the damper return springs. They are too tight, and "push back" on the key at the bottom of the stroke, jamming the jack as it tries to escape. I don't see too many U#s, but it certainly happens a lot on P22s,U1s and the T series pianos. I weaken the spring by pushing it against the damper lever with the Hart spring tool. Well, now that I think of it, there is one other potential cause- many times the shoe at the bottom of the balance hole is too thick, and the key will bind as it rocks, even though it seems free when you lift it. Pianotek makes a chisel tool that goes inside the key and removes some of the wood. -- --- David Graham <dcgrpt@earthlink.net>
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