"Bobbling" hammers on a new Yamaha U3. ( Please help! )

[Mitch Staples]

I've run into this problem in Yamahas and other pianos with the spring /
cord hammer return system.  I've always been able to make things work by
getting creative with the regulation (deeper dip, less blow distance, wider
let off, experiment with back check position and angle).  But after giving
it a little more thought it may be that there isn't enough friction in the
system.  You might first check the for loose pinning at the hammer flange.

Sincerely,

Mitch Staples

Ohio State University