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<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2>Don
--</FONT></SPAN></DIV>
<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2>My
timing must be off today. I just sent this question to the Yamaha email =
address
listed in the 2005 PTG Directory. When I clicked the send/receive =
button, that
message went out and your message came in. We'll see what they have to =
say, but
I think you have now provided me with the information I was hoping for. =
This is
very cool and gives me much to work with. I will do a couple of =
experiments, but
my guess is that since this is a regular undocumented feature of =
multiple
pianos your suggestion 2-1 may prove to be the answer. I'll report
back.</FONT></SPAN></DIV>
<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2>Thanks
--</FONT></SPAN></DIV>
<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=859332322-12072005><FONT face=Arial color=#0000ff =
size=2>--
Geoff</FONT></SPAN></DIV>
<BLOCKQUOTE style="MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr =
align=left><FONT
face=Tahoma size=2>-----Original Message-----<BR><B>From:</B>
pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] <B>On =
Behalf Of
</B>Donald Mannino<BR><B>Sent:</B> Tuesday, July 12, 2005 2:47
PM<BR><B>To:</B> Pianotech<BR><B>Subject:</B> Re: Mysterious =
unsolvable Yamaha
double-striking uprights<BR><BR></FONT></DIV><FONT =
size=3>Geoff,<BR><BR>This
is a common problem with this style of action, and is most often =
caused by the
combination of what has been touched on already by others (a few less =
likely
causes are at the end of this message);<BR><BR>- The hammer springs =
are
weak<BR>- The hammer friction is low<BR>- The jack springs are =
strong<BR>- The
damper springs are strong.<BR><BR>Depending on the individual piano, =
there are
different ways to eliminate it. Here are some options:<BR><BR>1. =
The
damper spoon timing is causing the resistance at the key to become =
very high
at the same time that the jack spring is being compressed for =
letoff.
This can be helped by weakening the damper springs or changing the =
spoon
regulation. The test is to press the pedal and see if the =
double-strike
still occurs. If not, then the damper spring / spoon regulation =
will be
the answer.<BR><BR>For spoon lift, it just depends on the piano. =
I have
sometimes made the dampers lift earlier so that the spoon friction and =
spring
resistance come earlier, so that when playing the key you =
automatically get
over that resistance before getting to letoff. That said, I have =
also
made the lift later and solved the problem - so it depends on the =
individual
piano.<BR><BR>For damper spring tension, use your grand rep spring =
tool to
pull back on a sample spring. Lift the damper individually by =
hand and
feel the resistance, then weaken the spring just enough that you can =
tell the
difference when pulling back on the damper head with your =
finger. Then
check for the bobbling.<BR><BR>2. As others mentioned, friction is =
often set
low on new actions to make sure they are reliable. You can try =
repinning
one hammer center to see if it helps, but I don't think that will make =
a
difference, actually.<BR><BR>This can occur in other pianos with =
the
same basic action design. This design (weak hammer spring, =
strong jack
spring) really does perform well and repeat well, but is subject to =
this kind
of bobbling when the settings are just right / wrong (depending on =
your point
of view!) Maybe it is a tribute to the consistency of the spring =
setting
processes that all of the pianos in this store are doing =
this!<BR><BR>OK, 2
more possible causes that are less likely:<BR>1. Manufacturer's =
sometimes
change the thickness of the butt felts in production in order to =
change the
"feel" of the letoff. If they decide to use a thinner felt, the =
letoff
feel is stronger (more like a grand). If they make it thicker =
the letoff
is smoother and power can be lower. If you look at the jack =
angle as it
meets the butts, you might see a difference between the actions and =
the action
model you looked at. This means that the bobbling is a trade-off =
that
the manufacturer has chosen to live with in order to get the other =
performance
levels they are looking for.<BR><BR></FONT>2. An unlikely but possible =
contributing factor is the angle of the action as it is installed in =
the
piano. For this to be off in multiple Yamaha pianos seems very =
unlikely,
but if the base of the action is mounted out too far out from the =
strings
(usually because the case parts are not fitting together right, or the =
keyboards are coming through with the capstans mounted in the wrong =
place,
etc) the action will be very subject to bobbling on soft play. =
Again,
this isn't likely in this case - just something to keep in mind for =
the
future.<BR><BR>Hope this helps some!<BR><BR>Don Mannino RPT
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