[sdiy] Yamaha digital piano issue

[Dave Brown]

I sent this yesterday and never saw it come through on the list.  I have an
acquaintance that called me from San Diego with an issue on their Yamaha
digital piano.  I don’t know the model number.

If they hold down Ab, Eb, and B, then A also sounds at full volume, which I
interpret to mean full velocity.  My first thought was a phantom key issue. 
Since there would be two switches per key for velocity, it also matches my
experience if only one switch is detected which defaults to full velocity.

The strange part is it also does it if Ab, Eb and C are pressed.  I don’t
know how you would have a phantom key issue with two different scenarios. 
Maybe it is an issue with the scanning driver, or two rows or columns with
some partial connectivity.  Anyway, it sounds like a keyboard or keyboard
scanning issue to me.

Any thoughts on what this could be?

Where does one get a product like this repaired?  I’m thinking any factory
service would module swap which would be very expensive.

Any DIY repair guys in the San Diego area?

David J. Brown
Email davebr at earthlink.net
Website http://modularsynthesis.com