[CAUT] Puzzler: Yamaha G7 clicks

[reggaepass at aol.com]

Thanks for your input on this.  I will try some thin CA on the knuckle glue joints of the worst offenders and the insertion of small round thingee between leather and cloth and report back.



Alan


-----Original Message-----
From: Fred Sturm <fssturm at unm.edu>
To: College and University Technicians <caut at ptg.org>
Sent: Sat, 26 Jul 2008 10:58 am
Subject: Re: [CAUT] Puzzler: Yamaha G7 clicks







Hi Alan,
    Maybe so, maybe no, but I have had clicks caused by very minor glue joint failure of the knuckle, where it really didn't seem to be loose, but turned out to be. So consider experimenting with a bit of thin CA (the cheap/fast way of addressing it) in case this can save you a good bit of time.

    I have experienced click on release caused by hard knuckle leather, though. Chinese piano with player. The owners liked to adjust it so that it played very quietly (it badly needed voicing), and the return noise was astounding - louder than the "music." Partly this is because of the way the solenoids instantly drop when the electrical impulse ends (fingers usually don't release the key that fast, especially when playing softly). There were other components to the release noise, but I traced most of the noise to the knuckle leather. I ran a cylindrical object (probably a 1/8" screwdriver shank, or whatever fit, maybe a Mannino broach or a paperclip) around between the felt and the leather, and it helped a good bit (after trying a number of other things, including brushing20and needling). In this case the leather was very hard to begin with, so I doubt it lasted. (This was not my customer, a dealer sent me out to deal with a complaint his regular tech couldn't deal with. I more or less satisfied the customer, reported my diagnosis to the dealer - needs knuckle replacement, and never heard more).

   I don't know if this would help, but it is possible to find table saw blades that will widen your knuckle slots the right amount (plywood blades, but it takes some experimenting with different brands and whatnot to get the exact size slot you want). And then a jig to set your shank in and slide it along a fence to make the cut. I forget the name of the guy (from CA) who designed and made a couple versions of this. It has been discussed on this list in the last few years. Faster than a file in the long run, if you do much knuckle replacement. Maybe not for an individual piano though.

 

Regards,

Fred Sturm

University of New Mexico

fssturm at unm.edu





 



On Jul 26, 2008, at 11:15 AM, reggaepass at aol.com wrote:


 
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 associateA 0observed 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 replacements.  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



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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