Greetings: I am working on a grand piano that has a noise coming from C2 that is eluding me. The symptom is a knocking that occurs on the downstroke. The noise disappears when the sustain pedal is depressed, but still present when the C2 damper is lifted individually. I initially thought it was the key end felt, but the fact that the noise remained when I lifted the damper manually excluded that as the source. This would also seem to eliminate the damper flange as the source, and I also checked that flange and it made no unusual noise by itself. It seems that there must be something going on within the wippen, but why the noise disappears when the sustain pedal is depressed puzzles me. Your help is appreciated. Patrick C. Poulson Registered Piano Technician 530-265-1983
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