Yamaha out of tune

[Avery Todd]

Elian,

   It sounds to me like something is shifting. I'm no expert at all, but
the first thing that comes to mind is the tightness of the plate screws.
Are they snug? If that first tuning was a pitch raise, that would of
course, contribute to *some* instability. But what you're describing
doesn't sound like that.
   Although it would probably be unusual in a Yamaha, you might also take
loose some strings to check the tightness of the bridge pins. I had a
piano once that wouldn't stay in tune. The bridge pins were very loose and
after epoxying them in (that was before CA glue), it held much better.
   Is there any possibility that the pin block is separating from the
back? I'm clutching at straws here, but with pianos, I've learned that
almost anything is *possible*.
   I've probably overlooked the most obvious, but I'm sure some of the more
experienced rebuilders on the list will come up with something better. In
the meantime, maybe this will give you some things to think about.

Avery

>My experience with Yamaha, and I have seen lots of them in the last years,
>is as the easiest piano to tune and Yamaha tunnings last a long time ( they
>have greater stability than many pianos. )
>
>Several month ago I was called to repair a Yamaha, it is an Upright model,
>serial  M1JD3467278, not much to do, an action adjustment, some hammer
>reshaping, very much out of tune, but I considered it was dur to the long
>time without service. I took the pitch up, tuned it to 442, and I convinced
>him to have it tuned twice for the next month.
>
>After that he kept calling me and every time I check the piano is out of
>tune again, tuning won´t last a month.
>
>I checked tunning pins, they are firm and look excellent condition.
>I checked the bridge, hitch pins.
>Cheked humidity and temperature
>
>Also pitch stays were it is (442) in general,  when I tune it some strings
>seem to be higher others lower, to give you an idea they move about half
>beat appart from each other. I haven´t seen anything like it.
>
>The place where the piano is located is cool, stable temperature, there are
>no heaters nor air conditioners,
>
>The pianist plays nicely, doesn´t strike the keys.
>
>If anybody has any idea........
>
>
>Thank you
>
>Elian


___________________________
Avery Todd, RPT
Moores School of Music
University of Houston
Houston, TX 77204-4893
713-743-3226
atodd@uh.edu
http://www.music.uh.edu/