Mysterious unsolvable Yamaha double-striking uprights

[Geoff Sykes]

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I mentioned the plastic jacks because it was the only difference that I
could see. I don't see why they would make any difference either, though =
I
have not actually taken one out and held it side-by-side a wooden one.
=20
Loose hammer flanges sounds like a real likely culprit. How many times =
have
we checked the pinning on a brand-new hammer flange only to see eight or =
ten
swings? Since this is dealer prep I think I was actually avoiding that =
as a
possibility. However, now that it's been suggested as a possible =
solution I
can take that back to the dealer and find out how much they want to =
invest.

=20
Springs will be the test after that. All I need to do is slip it out =
from
under the loop and stretch it out a bit, right?
=20
-- Geoff
=20

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On =
Behalf
Of Susan Kline
Sent: Monday, July 11, 2005 11:29 PM
To: Pianotech
Subject: Re: Mysterious unsolvable Yamaha double-striking uprights


Interesting about the plastic jacks, though I don't see what difference =
it
would make.=20

For some kind of relief, you might try repinning the hammer flanges =
firmer.
Also make sure there isn't a rail set up to stop the motion of the jacks =
too
soon.=20

If it's still driving you crazy, you might widen the letoff a hair, and
maybe strengthen the hammer springs a little bit.=20

Good luck - I've seen this on Yamaha big uprights and also on Kawai big
uprights, though not all of them, or this bad. For some reason, I =
haven't
found it on consoles or short uprights. Maybe I just didn't look ...=20

Susan

At 11:04 PM 7/11/2005 -0700, you wrote:


Greetings --
=20
I did a dealer prep on a brand new, fresh out-of-the-box, Yamaha MX500 P
upright today. Every single note double-struck when played softly. I =
checked
regulation and had to adjust lost motion on every key. Let-off also =
needed
to be adjusted, but only on about 10 keys. When I finished these two
adjustments the regulation may not have been perfect but it was =
certainly
close enough. Still, every single note was double striking when played
softly. (Definition of "softly": Playing the note faster then when you =
are
checking let-off but slower than it takes to actually check.)
=20
What I am witnessing is this: When I play the note, just before the jack
releases from under the butt the hammer jumps off the jack prematurely =
and
strikes the string. After striking the string the hammer then bounces =
back
onto the jack, which is still in it's pre-release position. Continuing
through the keystroke results in the hammer striking the note a second =
time
as the jack finally releases from under the butt.=20
=20
This was something new to the store manager so I called an associate. He
suggested I go through the routine I had just completed, but otherwise =
could
offer no further suggestion. OK, so I decided to tune the thing while I
pondered the matter further.=20
=20
Aha! Tuning finished. Let's see what the other Yamaha uprights are =
doing. I
checked six other, (not used), Yamaha uprights on the floor, (none of =
which
I had prepped, but all of them allegedly prepped), and every single one =
of
them exhibited the same double-strike behavior. For comparison I then
checked some NON Yamaha uprights and they all behaved properly. I =
finally
checked the showroom Yamaha action model, and it, too, was behaving
correctly. BUT... It was then that I noticed that all the Yamahas used =
in
this test had plastic jacks. The Yamaha action model, as well as the
non-Yamaha uprights used in this test, all had wooden jacks.=20
=20
That's all the clues I have. Anybody have any idea what's going on, and =
what
can be done to correct it?
=20
Geoff Sykes
Assoc. Los Angeles Chapter


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