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<DIV><FONT face=Arial size=2> Mark</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2> I've seen this problem for =
years. It first
showing up in years1976&77. The plated center pins flake off in the =
bushing
cloth and voila,mass friction Yamaha was very good about paying for this =
type
ofe warranty repair so I'm guessin it was fairly wide =
spread.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>. Tis a good =
idea to use a
roughend reamer to remove crud,Then polish and reinstall a real =
brass
center pin. I've done massive amounts of this kind of repinning, =
largely
in the hammer flange(wippen) but have done several complete damper tray
assemblys as well. Once there goin bad I repin everything. If its =
under
warranty guess who I'd be calling?</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2> Best Dale =
Erwin</FONT></DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>
<A href="mailto:mark@nhpianos.com" title=mark@nhpianos.com>Mark =
Dierauf</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A =
href="mailto:pianotech@ptg.org"
title=pianotech@ptg.org>pianotech</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, May 04, 2001 5:06 =
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> CP contamination on =
Yamaha S
400-B</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2> I had a customer complain =
about the touch
on their Yamaha grand and discovered that it weighted off at 66 grams =
at
middle C. When I checked the hammer flange I found that I could only =
get one
swing, and that the bushings had a black residue on them. Closer =
inspection
showed that this residue was also on the center pins as well as =
slightly in
the wood surrounding the bushings. The residue on the pins themselves =
rubbed
right off, and the pins looked shiny and new without any signs of =
buildup or
corrosion. I repinned one to normal tolerances and the cloth felt =
as if
it had normal resiliency, and the downweight dropped by 11 grams. =
I also
found that the wippen flanges had the same residue, but hadn't seized =
up the
way the the hammer flanges had. They seemed to be *slightly* on the =
tight side
but still within normal tolerances (I didn't have my little spring =
gage with
me). The jack & rep lever bushings were normal bright red cloth, =
and
perfectly free.</FONT></DIV>
<DIV><FONT face=Arial size=2> I have an appointment to =
return and repin
this action, but before I do I wondered if anyone else has run across =
this
before. Could this be something that Yamaha did at the factory? =
although
I've certainly never seen it in their other grands, this is the first =
S series
grand that I've serviced. The customer bought it used last year and so =
doesn't
know it's history. Does anyone know of any center pin lubricants that =
react in
this way? Is the problem likely to return after repinning? The serial =
# is:
</FONT><FONT face=Arial size=2>U3894763</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks, </FONT></DIV>
<DIV><FONT face=Arial size=2>Mark
Dierauf</FONT></DIV></BLOCKQUOTE></BODY></HTML>