Fallboard screw (Yamaha)

[Cy Shuster]

Aha!

I just solved a mystery sound on the aforementioned 1974 Yamaha C3.  G#3, 
when played loudly, had this very odd, fast buzz, off-pitch, and lower by a 
couple of octaves.  I'll try to record it next time I'm there.  The 
sensation I had was that the hammershank was touching something: you could 
feel the vibration in the key.  It would happen briefly, just at the 
beginning of the keystroke, maybe 2/10 of a second.

I started reaching around all over the piano, as you do, and noticed that it 
went away when I touched that %^& fallboard.  I saw a worn place on the 
extreme right-hand end, about 3/8", near the top of the stretcher.  Sure 
enough: the fallboard was just barely touching the stretcher there, and 
nowhere else.  Move it a fraction of an inch away, and the buzz disappears.

There's no sign of a missing button anywhere.  I'll try to dig up a clear 
one for the stretcher.  I can't see any way to adjust travel with the pivot 
hardware.  I tried over-extending the slow-close spring, but it didn't help.

--Cy Shuster--
Bluefield, WV