[CAUT] Puzzler: Yamaha G7 clicks

[reggaepass at aol.com]

First, let me say that I have never worked on a Yamaha of
this vintage before.  The
craftsmanship is excellent.  It has
Schwander wippens.  First we
thought it was hardening of the jack felt punching.  When needling and then replacing that did not solve the
problem, we redirected our attention to the repetition lever, brushing,
needling, and then replacing the drop screw leather pad ("bumper").  Still no change.  We even tried replacing the piece of
action cloth under the repetition lever height adjusting screw (Schwander, right?), just in case
that had somehow gotten hard enough over the years to make noise when the
lever came back up.  Nope, not that
either.




None of the keys were chucking (on a sixty-five year old instrument that has probably never had any major servicing!).  I have seen that condition either cause or contribute to this kind of noise before.  But if any thing, the balance holes are tight on the key pins.



 



Your last thought wins you bragging rights, Dan.  We decided to brush some knuckles.  An associate observed that the nap of
the leather did not lift as it has on all of the other pianos on which we have brushed
knuckles.  So we endeavored to
replace the knuckle.  The original
had a core about 1.6 mm thick, whereas all of the replacements we had on
hand—Renner, Abel and Tokiwa—have cores that are around 2 mm thick.  Also, the original slot was too shallow
for any of the repl
acements.  So we
used a 2 mm wide file to both widen and deepen the slot.  New knuckle installed (used Titebond
Trim and Molding glue, which seems to work well), noise gone. Well, as we so often say in the piano world, “One down,
eighty-seven to go!”  




We seem to identified the fix, though I must admit that I'm not sure how it is that a hard knuckle could cause this problem.  (Then again, we humans have appreciated sunrises long before we understood what we were actually witnessing when we saw one.)  If anyone knows 1) WHY the hard knuckle leather causes this click on a quick release, or 2) HOW to treat the existing knuckle leather (magic potion, special armadillo comb, etc.), PLEASE do share your insights (hopefully before we file 87 more knuckle slots!).

 



May this save someone else all of the time we
spent trouble-shooting.



 



Cheers,



 



Alan Eder



 












-----Original Message-----
From: Dan Reed <pianoarts at tx.rr.com>
To: College and University Technicians <caut at ptg.org>
Sent: Fri, 25 Jul 2008 8:57 pm
Subject: Re: [CAUT] Puzzler: Yamaha G7 clicks








In addition to hard jack stop felt....Some more of the usual
suspects....



Hard drop screw felt on the rep lever, snapping back on a quick
release, hitting the drop screw.....


'Chucking key...key bouncing on the balance rail on a quick release...


Hard knuckle...bouncing on the jack top...


Dan


Dallas
0A

On Jul 25, 2008, at 7:36 PM, reggaepass at aol.com wrote:


<excerpt>Yes, you read that correctly, this is a Yamaha model G (not
C) 7, s/n 3xxxxx.  When the key is released slowly, the click isn't
noticeable.  However, on a quick release, it is annoyingly prominent.
 What is the cause?


Alan Eder



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