Pianotech

  • 1.  Lack of response on hard blows

    Registered Piano Technician
    Posted 06-29-2023 22:25

    2012 Schimmel C-208

    Gorgeous piano. No real problems. Lives in a perfect environment as far as stability is concerned. And customer has no issues. He loves the piano as is. But when I'm there to tune it I notice that when I do a sharp test blow the key feels like it's got a "governor" on it. The harder I play the note, the less response I get from it. On hard blows it feels like it is suddenly being held back, like, for lack of a better term, like a marshmallow has suddenly gotten in the way. As I think about this I'm thinking that it's possibly poor jack/knuckle alignment. Like the jack is too far back. But I have not had the opportunity to pull the action and experiment with this adjustment. Before I recommend some regulation to the customer I thought I might check in here to see what others think about what I should be looking for. 

    FWIW, the only other time I have experienced this same issue was with a Samick Knabe piano. No matter what I did I could not make it any better. In that situation I was finally convinced it was an uncorrectable factory action geometry problem and finally gave up. 



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    Geoff Sykes, RPT
    Los Angeles CA
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  • 2.  RE: Lack of response on hard blows

    Posted 06-29-2023 22:38
    Back checks prematurely rub the hammers on hard blow .?

    Alexander Brusilovsky




  • 3.  RE: Lack of response on hard blows

    Registered Piano Technician
    Posted 06-29-2023 22:44

    Sounds like the backcheck is interfering with the hammer rising to the string.  Put a finger on the hammer while you push down on the key and let the key go through let-off.  The key and hammer should move freely even if you put a little extra pressure on the hammer as it rises.  It's also possible that the hammer tail isn't shaped properly and scrapes the backcheck as the hammer rises.  Also, many Korean and other brands shape the hammer tails before they're bored, so when mounted the tails are not perpendicular to the shanks, and require the backchecks to be angled to match.  If this is the case, get a jig and reshape the hammer tails.  The hammers will check much better and reduce wear on key bushings, hammer flanges, etc.

    Your main complaint is that the harder you play the key, the more sluggish it feels.  Flexing of the hammer shank and rubbing of the hammer tails on the backcheck is very common, and I've found this to be the culprit in almost every case I've had those symptoms.



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    Paul McCloud, RPT
    Accutone Piano Service
    www.AccutonePianoService.com
    pavadasa@gmail.com
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  • 4.  RE: Lack of response on hard blows

    Registered Piano Technician
    Posted 06-30-2023 00:34
    I concur with Alexander and Paul. Pull the action and push back on the offending back checks. And while you've got the action out, check the jack/knuckle alignment, too. 





  • 5.  RE: Lack of response on hard blows

    Registered Piano Technician
    Posted 06-30-2023 06:25

    Geoff,

    Sounds like this could be the work of one of my favorite country music duos, Cheatin' Jack and Too Close Backcheck. Like Alexander, Paul and Wim have said, more likely the latter. 

    Before reshaping tails or even bending back check wires, you might want to take a moment to loosen all of the action bracket screws, seat the top stack towards you and retighten in this sequence recommended by Yamaha: screws of the end brackets first, then the rear screws of the other brackets, and finally the front screws of the other brackets (which may be angled backwards). Believe it or not, if the front action brackets screws are angled and they are tightened first, that can push the stack back enough in some cases to cause the kind of tail-to-backcheck interference it sounds like you are describing.

    "This has never happened to me, but I knew a guy..." who once tried more time-consuming and invasive measures only to later realize that it was simply due to the top stack having been installed just a bit too far back. ;-] Definitely worth taking a minute to investigate.

    Best,

    Alan



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    Alan Eder, RPT
    Herb Alpert School of Music
    California Institute of the Arts
    Valencia, CA
    661.904.6483
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    Original Message


  • 6.  RE: Lack of response on hard blows

    Registered Piano Technician
    Posted 06-30-2023 06:36

    Last resort check for key stick flex and/or balance rail not bedded



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    Larry Messerly, RPT
    Bringing Harmony to Homes
    www.lacrossepianotuning.com
    ljmesserly@gmail.com
    928-899-7292
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    Original Message


  • 7.  RE: Lack of response on hard blows

    Registered Piano Technician
    Posted 06-30-2023 08:57
    The jack is too far forward, not back. It slips out too soon.



    Sent from my U.S.Cellular© Smartphone






  • 8.  RE: Lack of response on hard blows

    Registered Piano Technician
    Posted 06-30-2023 12:32

    AHA! Thanks, all, for your responses. While I always follow the Yamaha recommended method of screwing down the action, I was unaware that this procedure could affect hammer/backcheck alignment. Yes, it only takes a little shank flex at the wrong moment to cause the tail to touch the backcheck a little tiny bit when playing hard. And now, with this new understanding, I remember that this customer has taken the stack off himself several times in order to install a DIY midi device under the keys. Next time I'm there I will pull the action and reinstall the stack, correctly, to see if that makes a difference. Thanks all.



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    Geoff Sykes, RPT
    Los Angeles CA
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  • 9.  RE: Lack of response on hard blows

    Member
    Posted 07-01-2023 15:38

      It very likely is a hammer rubbing the tail and re screwing the action brackets following the Yamaha sequence may fix the issue. Beware if the owner has played with the action- the holes in the frame may be enlarged. Next I would check the backchecks catching the tails . You could also have some loose pinning on the rep levers- ask me how I know....

        The Yamaha method  starts with the front hole of the treble right most bracket skips the middle bracket put  screw in the front hole of bass bracket goes to the back hole on the bass bracket skips the middle brackets goes to the back hole of the treble bracket. next screw goes in the back holes of middle brackets from right to left ; proceeds to the front holes of middle brackets going left to right thus:

                                            3                7                6                    5                       4

                                            2                  8              9                    10                      1

                                           2                                                                                  1 



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


  • 10.  RE: Lack of response on hard blows

    Posted 07-02-2023 08:59

    I worked on an older Steinway recently and the touch was heavy so I suggested regulation. Turns out when I inspected the action everything was pretty close but the action hadn't been screwed down properly and this threw everything off. A simple fix and the customer got a smaller bill than anticipated.



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    Don Dalton
    Chester VT
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    Original Message