Yamaha Jack issue

[Fenton Murray]

Oh yea, Yamaha's from the 60's and early 70's had this problem. 
Regarding the non returning jack in an upright with all regulation and friction proper in the action, do not forget the key. It must not have excess friction and must be balanced correctly. Also check hyper active whip assist springs.
Fenton
  ----- Original Message ----- 
  From: Avery Todd 
  To: Pianotech List 
  Sent: Thursday, March 20, 2008 8:50 PM
  Subject: Re: Yamaha Jack issue


  I've never heard of that on Yamaha's. I "think" it was Samick that had that problem. 

  Avery Todd
  Houston, TX 


  On Wed, Mar 19, 2008 at 10:34 PM, Greg Newell <gnewell at ameritech.net> wrote:

    Steve,

                    Are you sure this isn't a center pin plating issue? I recall reading somewhere that the plating comes loose and binds in the action center. The more you play it the worse it gets until you stop for a while.



    Greg Newell

    Greg's Piano Forté

    www.gregspianoforte.com

    216-226-3791 (office)

    216-470-8634 (mobile)



    From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Steve Blasyak
    Sent: Wednesday, March 19, 2008 12:29 PM
    To: pianotech at ptg.org
    Subject: Yamaha Jack issue



    Terry,
     
    I had the same problem with an M 500 a couple of weeks ago. I have had similar problems/ issues with consoles or uprights in the past usually in the high treble were the hammers are lighter. I always considered this a key weighting issue. This particular instance was at B 1. Checked all friction, whippen, jack and hammer. All good, in fact if anything they were pinned too loose. Tried more lost motion, lubricated jack, teflon on butt leather. Increased key dip. Increased jack spring tension. Nothing worked. Well in the end, with the damper pedal depressed and rapidly playing the note it would fail after about twenty repetitions. Under normal playing, if the jack failed to return under the hammer butt, as soon as you release the damper pedal the jack would slip back under the hammer butt. So I told the client "that's as good as it gets", and called it a day. Driving away, I tried to rationalize that it was an unexplained phenomenon. I could not escape the feeling of failure to solve the problem.
     
    One thing that was mentioned by someone I can't remember who. What would the key bed have to do with this phenomenon?  
     
    Steve Blasyak
    Orange County Ca.
     
    Pura Vida




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