Pianotech

  • 1.  Petrof Zing

    Registered Piano Technician
    Posted 04-24-2019 19:57
    Hello All,

    I serviced a Petrof upright today. It had a very noticeable zing in quite a few of the notes. See the attached video. The piano was moved from the Los Vegas area four months ago. I tuned and pitch raised it approximately 4-8 ¢.

    I first tried needling the hammers, including sugar coating. That didn't yield any results. No screws loose or other loose objects. Initial research revealed that the problem could be related to the agraffes.

    1) Do you think this could be the case?
    2) If so, how would I go about fixing it?

    Thank you in advance,

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    Benjamin Sanchez
    Professional Piano Services
    (805)315-8050
    www.professional-piano-services.com
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  • 2.  RE: Petrof Zing

    Registered Piano Technician
    Posted 04-24-2019 20:04
      |   view attached
    Hold one, I'm having technical difficulties with the video....

    Hope the zing comes though. I'm not sure if it will in the video.

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    Benjamin Sanchez
    Professional Piano Services
    (805)315-8050
    www.professional-piano-services.com
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    Original Message


  • 3.  RE: Petrof Zing

    Posted 04-24-2019 21:34
    Did you check the bridge pins?

    John Formsma, RPT
    New Albany, MS





    Original Message


  • 4.  RE: Petrof Zing

    Posted 04-24-2019 21:44
    It has agraffes in that section right? I'm suspecting it has something to do with them.

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    "That Tuning Guy"
    Scott Kerns
    www.thattuningguy.com
    Tunic OnlyPure, TuneLab & Smart Piano Tuner user
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    Original Message


  • 5.  RE: Petrof Zing

    Posted 04-24-2019 22:05
    Oops, I skimmed over the part about it having agraffes. You can check them along with the bridge pins. In plain wire strings, zings are only going to happen at the contact points. Could be bridge-related, agraffe-related, or backscale related.

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    John Formsma, RPT
    New Albany MS
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    Original Message


  • 6.  RE: Petrof Zing

    Member
    Posted 04-25-2019 01:08
    It looks to me that the hammer felt is not centered on the strings - more felt on the right side of the hammer needs to contact the string. Try loosening the hammer flange screws and centering the hammers. A little side squeezing using vice grips may help as well as checking the damper felt seating and hardness of the felt. Check the positioning of the felt on the practice rail to make sure it is not in contact with the strings. A little levelling of the strings may also help as well as checking the string/bridge pin seating. How old is this Petrof

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    James Kelly
    Pawleys Island SC
    843-325-4357
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    Original Message


  • 7.  RE: Petrof Zing

    Registered Piano Technician
    Posted 04-25-2019 08:51
    Hi Ben, I'm hearing a super high partial on the attack. 

    A flat blade screwdriver placed between the strings at the agraffe and pried up slightly using a twisting motion on the blade will improve agraffe zinging.  What you're doing is shaping the wire at the point where it passes through the agraffe so that it conforms to the agraffe better.

    Lar

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    Larry Fisher
    Owner, Chief Grunt, Head Hosehead
    Vancouver WA
    503-310-6965
    Working the gravy zone for the rest of my days.
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    Original Message