Yamaha out of tune

[R. Goodale]

I once had a similar situation, also a Yamaha, a P2). One day while
tuning it I noticed air around my feet. Turns out the piano was sitting
on top of a floor air-duct. It was not visable at all with the piano on
top. It it easy to imagine how this could change things in a short order
of time.

Rob Goodale, RPT