[pianotech] More on Yamaha Sticking C6 Key Problem

[Joe Goss]

Hi Robert,
>From your description I tend to think that no amount of Protec or Goose 
Juice will solve your dilemma.
Only repining of the sluggish centers to their correct tolerances will.
Do check all centers in the action train on that note and repin as or even 
if not needed. My thinking is that there is too much glue on the bushing 
cloth or abrading of the center pin.
The works for a while then freezes up is an indicator of my hunch.

Joe Goss BSMusEd MMusEd RPT
imatunr at srvinet.com
www.mothergoosetools.com
----- Original Message ----- 
From: "David Love" <davidlovepianos at comcast.net>
To: <pianotech at ptg.org>
Sent: Sunday, February 14, 2010 5:38 PM
Subject: Re: [pianotech] More on Yamaha Sticking C6 Key Problem


It certainly seems from your description that the jack center could be a bit 
tight.  You should be able to tell by rolling it and releasing it comparing 
it with others around it.  Try lubricating with some Protek. That often 
helps on Yamaha centers that tend to develop excess friction periodically 
for some reason.  While you're at it lubricate the hammer flange centers and 
the wippen centers.  Also, it could be that the balancier is regulated too 
low combined (perhaps) with a weak repetition spring.  If the jack protrudes 
to far above the balancier it will be inhibited from getting back under the 
knuckle.  Increase the tension on the rep spring so that you get a very 
positive rise.  The speed should be similar to how fast your arm would move 
to toss a tennis ball about 18 inches in the air (one way to think about 
it).  Also, be sure that the jack is aligned correctly with the back of the 
knuckle core.  If you think the damper may be influencing things check the 
repletion with the damper pedal engaged.

David Love
www.davidlovepianos.com


-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf 
Of rsfinley at charter.net
Sent: Sunday, February 14, 2010 2:53 PM
To: pianotech at ptg.org
Subject: [pianotech] More on Yamaha Sticking C6 Key Problem

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