Pianotech

  • 1.  Yamaha action stack shifting after removal

    Member
    Posted 25 days ago
    This occurred a few weeks ago. I was called by one of my church clients, which has a Yamaha C5 #5956482 (2001) to resolve an issue with a keystick making a noise (for brevity I won't go into the details). It required removing and replacing the action stack. The repair went smoothly, and problem was solved. Got a call the next day from the church pianist that most of the keys in the upper half of the scale wouldn't play. ​I met her at the piano a couple days later, and she said that most of the kays were now playable except for a handful in the treble. The problem keys were where the hammers were being caught by the backchecks before they could complete their strokes. I was strongly suspicious that the action stack had somehow shifted to the rear by some sliver of an inch. After looking closely at the bracket notches made in the keyframe for each of the end brackets, I saw that the notches were deliberately made about an 1/8" longer than the brackets, and that shims had been inserted at the front of the notches, filling a space between the end of the notches and the front of the bracket "toes." Acting on a hunch, I loosened all the action bracket screws some, took a screwdriver, and with the palm of my hand, thumped it against the "heel" of each bracket, and tightened the screws--problem solved! Had the pianist come and apply some rapid-fire repetition on the former problem keys, and they all passed with flying colors! Called Yamaha support a few days later, and the tech pulled a grand action as we spoke and he noted that it had the shims in the bracket notches. He made a comment that Yamaha grand keyframes are more flexible than other brands. I suggested that the shims were put in after the stack was set in place (but before the stack was screwed down), and the brackets applied a forward pressure to the shims, which was released when I removed the bracket screws & it shifted. Thought I'd put this out there for anyone who has experienced the same thing, or who may see it happen in the future.

    P.S. Yes, I did remove and replace the bracket screws in the correct order for Yamaha grand action brackets!

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    Robert Sluss
    Lake City FL
    (386) 752-1888
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  • 2.  RE: Yamaha action stack shifting after removal

    Member
    Posted 25 days ago
    Drill holes for bridge pins to index the bracket feet. I do it all the time. Not just front-to-back but side-to-side too.

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    Regards,

    Jon Page
    mailto:jonpage@comcast.net
    http://www.pianocapecod.com
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  • 3.  RE: Yamaha action stack shifting after removal

    Member
    Posted 25 days ago
    Huh? What do bridge pins have to do with action brackets? Are you referring to something done in rebuilding?

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    Robert Sluss
    Lake City FL
    (386) 752-1888
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  • 4.  RE: Yamaha action stack shifting after removal

    Registered Piano Technician
    Posted 25 days ago
    I think he means for indexing the location of the stack on the key frame. 





  • 5.  RE: Yamaha action stack shifting after removal

    Member
    Posted 24 days ago
    Ok. He would have to understand that the issue was because of the shim, not the position of the brackets. The idea of the shim is apparently to provide a well-seated stability. I suspect Yamaha did not intend for there to be a fraction of a millimeter give when the screws were loosened that would have to be reversed before the screws were fastened down. I could potentially see where a bridge pin behind the bracket heel could possibly prevent backward shift…but gosh, that shift was probably 1/64", or 1/128". If the bridge pin was installed and put forward pressure on the brackets, would we see things get messed up again in a different way? There is a law of unintended consequences…

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    Robert Sluss
    Lake City FL
    (386) 752-1888
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  • 6.  RE: Yamaha action stack shifting after removal

    Member
    Posted 21 days ago
    Somewhere I have a tip that the action bracket screws on a Yamaha grand need to be put on in a certain order and pattern.  Basically you start at the right bracket hole closest to the keys in the high treble. Second screw goes in the bracket at the bass end. 3rd screw in the same bracket on the string side. 4th on the right bracket hole on the string side then go counter clockwise until complete. it is important to use the same screws that came out of the brackets. here is a crude diagram




                             x 3            x 6         x 5        x4

                             x2             x7           x8         x1

                                                               < --------


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    James Kelly
    Owner- Fur Elise Piano Service
    Pawleys Island SC
    (843) 325-4357
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