[pianotech] More on Yamaha Sticking C6 Key Problem

[Isaac Sadigursky]

Hi,Robert!
I had watched this thread and here are my 2 kopeks:
I would suspect "Reversed Pinning" situation:The Jack Center Pin  
rotates in the Bird Eye and is too tight in the bushing..
Re-pinning will take care of it.
During repetitious playing the Center Pin heats-up and becomes too  
tight,when it cools-off-things are normal ,again.In that condition the  
center pin passes any test..

When your technician will do re-pinning,do the following;
Upon removing the Center pin from the Jack,MEASURE the Pin
2]Select exactly the SAME SIZE  Center pin and if you can push it  
inside the Jacks Bird Eye with your finger nail-it means it's rotating  
there..You must go to next 1/2 size larger Center Pin
3]Try to push that Original Pin in the Felt Bushing and it  
will ,probably,be TOO TIGHT
I had found that "Reverse Pinning" in many brand new parts..
I hope,I made myself clear on that.
Good Luck!
isaac Sadigursky, RPT.
Los Angeles Chaper..
On Feb 14, 2010, at 2:52 PM, <rsfinley at charter.net> wrote:

> Here are some more observations on the intermittent problem with the  
> C6 on my Yamaha G1 Piano.
>
> When I play the key the first time, the note usually sounds, but if  
> I play repeatedly and quickly after that, it stops sounding. I have  
> to wait a few seconds after that for the key to recover, before it  
> will play again. It seems there is a delay of a few seconds when  
> part of the action is slowly getting back into the position when the  
> key can be played. I am puzzled why there is this delay.
>
> When I take the action out and put it on a table, I cannot reproduce  
> the sticking key effect for C6, even if I simulate the presence of  
> the string using a hard book held some distance above the hammer (of  
> course the hammer will not rebound in the same way as for a string).  
> I can cause the hammer to move in fast repetition without any  
> blocking effect. The sticking key effect only occurs when the action  
> is back in the piano. Although I doubt it,  I am wondering if this  
> is a combined effect of the damper and the action causing this  
> sluggish operation, although the damper for C6 seems to be working  
> fine.
>
> When I look at action for C6 (difficult to see everything due to the  
> proximity of the actions of the other keys, everything appears to be  
> intact.  I haven't removed the whippen assembly for C6 yet to  
> examine it in detail. Maybe I should do that.
>
> Could anyone throw more light on this? Thanks for your advice.
>
> Robert