Yamaha Tuning Instability

[Robin Hufford]

Terry,
     There is a structural problem, as you suspect, not environmental,  and that is the fact that the pinblock is not well fitted to the plate flange, notwithstanding the factory line on this.  Also, the plate screws may be loose.  This is a common problem,  as mentioned here, on Asian pianos and on Kawai's, particularly, and Yamaha's.  I have heard the explanations that the piano does not have to have the flange well-fitted to be stable, or is stable enough, and that every other thing is to be blamed for this type of instability,  and, after just these
explanations, gone on to let the tension down, tighten plate and pinblock bolts, fill the gaps, retighten plate bolts, bring to pitch and then find the piano to be rock stable after a few tunings.  The customers and other techicians who have referred them to me for this problem also note this.  Why look for esoteric explanations in the face of an easily perceived deficiency.
Regards, Robin Hufford

Farrell wrote:

> I agree that you state logic, but the stable microgrand is actually more in the direct path of the AC vent. The Yamaha does not get blown on. The pianos are in her separate studio. It is a former in-law type house. No cooking is done in there, nor are showers taken, so humidity is presumably fairly stable, just varying with outside general directions. As I stated, she will purchase a cheap hygrometer and start monitoring RH. No windows near the Yamaha. The microgrand is next to sliding glass doors that are never opened. No plants in house. No holes in wall.
>
> All these factors raise my concerns regarding some type of structural condition.
>
> Terry Farrell
>
>

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