Yamaha U1 regulation problem - last .. lost motion.

[Isaac OLEG]

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And having that smooth key stroke beginning help even light players to take
some power for the remaining of the stroke, while if the resistance is
immediate, their fingers are too much slow down and they don't go thru the
whole stroke.


Cheers and a good Week end

Isaac OLEG

Entretien et réparation de pianos.

PianoTech
17 rue de Choisy
94400 VITRY sur SEINE
FRANCE
tel : 033 01 47 18 06 98
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  -----Message d'origine-----
  De : pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]De la
part de Dave Nereson
  Envoyé : samedi 8 mars 2003 12:26
  À : pianotech@ptg.org
  Objet : Re: Yamaha U1 regulation problem



    ----- Original Message -----
    From: Tom Driscoll
    To: pianotech@ptg.org
    Sent: Thursday, March 06, 2003 10:06 PM
    Subject: Yamaha U1 regulation problem


    List

                I recently serviced a U1 vertical for a first time client.
Excellent piano very little wear and -tuned up quite well.

                I did however find lettoff to be over !/4 “and inconsistent.

                I adjusted to 1/8” –and took up lost motion. Tightened
action screws. The key dip and after touch were sufficient, and the jacks
are free to travel away from the butts---no interference from that
adjustable rail—(sorry, I forget Y’s nomenclature on that component)

                My client has a light touch and the action still stutters

    I returned, shortened blow distance readjusted lost motion, and adjusted
spoons to re-correct damper timing.

                My client called again with the same problem and called
other technicians for advice also

                I know bobbling hammers can be a problem on Yamaha verticals
and I’ve worked on hundreds of these, but I can’t shorten blow any more and
as I mentioned, keydip-aftertouch are correct. I’m hesitant to increase
lettoff back to its original excessive amount, so esteemed colleagues ---Any
suggestions? I’m going back next week.

                P.S.  Backchecks are also adjusted---I.E. catchers are not
bouncing out or off of the backchecks

                Tom Driscoll



        I also encountered bobbling hammers on many Yamaha verticals during
my eight years with a Yamaha dealer.   One of the most common responses from
Buena Park when I asked for technical help was to tell the customers to
press the keys all the way to the bottom with no hesitation mid-stroke.
[Almost any vertical can be made to bobble by hesitating mid-stroke].  Your
client's light touch might at times be "hesitating" enough on certain blows
to cause bobbling.  But I realize telling people they're playing "wrong" is
a delicate situation.  The only other thing the tech. folks at Yamaha would
suggest was to check the pinning and the spring strength.  I think too tight
a center pin can contribute to bobbling as well as too weak a hammer return
spring (the Schwander type springs are considerably lighter than the
traditional long ones mounted on a separate spring rail).  [A side note not
really having to do with this problem:  The let-off on the pianos with the
Silent Piano feature is 1/4" or wider, I believe, and supposedly the touch
doesn't suffer.  Haven't played one enough to know, though.]

            --Dave Nereson, RPT, Denver

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