Pianotech

Back to discussions
Expand all | Collapse all

jack issues

  • 1.  jack issues

    Registered Piano Technician
    Posted 01-18-2018 17:11
    This is a 1987 Yamaha model C-108. On A3, and so some degree, A4, the jack fails to reset, but Only when the damper pedal is down. I can play it rapidly without issue when the damper pedal is Not used. Other keys work just fine. So, 1st I put a little CLP on the jack flange - no diff. The regulation is good, there is no corrosion on the spoon, the key is not binding.
    Eventually I did the following:
          strengthened the jack spring
          repinned the jack flanges
          tried giving the key more lost motion [lowered the capstan]
          tried raising the hammer rail
          lubed the wippen flange
          put some CLP on the buttskin [why not, at this point?]
    Nothing helped. When the damper pedal is in use, Why are these two keys not getting enough energy to reset when everyone else is?

    ------------------------------
    Sheffey Gregory, RPT
    [
    ------------------------------


  • 2.  RE: jack issues

    Registered Piano Technician
    Posted 01-18-2018 17:43
    Sheffey

    Look at the damper lever felt where the spoon hits it. Even with a smooth spoon, if the felt is worn out, it will hang up on the spoon. 



    ------------------------------
    Willem "Wim" Blees, RPT
    Mililani, HI 96789
    ------------------------------

    Original Message


  • 3.  RE: jack issues

    Registered Piano Technician
    Posted 01-18-2018 18:25
    ​Sheffey,
    It appears the wippen is not returning completely, but only when assisted by the damper spring. Check the wippen flange bushing. It may be necessary to remove the wippen to check for smooth travel throughout -- simply applying Proteck without checking the pin tightness could reveal the problem. If that doesn't reveal the problem, add a lead to the back of the key to see if that corrects the problem. Many low grade pianos manufactured in the U.S. didn't have leading in the back of the key which resulted in the symptom's you described, although I would be surprised if Yamaha didn't balance the keys properly.
    Roger

    ------------------------------
    Roger Gable
    Gable Piano
    Everett WA
    425-252-5000
    ------------------------------

    Original Message


  • 4.  RE: jack issues

    Posted 01-20-2018 11:28

    It appears the wippen is not returning completely, but only when assisted by the damper spring. Check the wippen flange bushing. It may be necessary to remove the wippen to check for smooth travel throughout -- simply applying Proteck without checking the pin tightness could reveal the problem.
    Roger Gable,  01-18-2018 18:24
    Yes, I think you're on to something! I've had the same problem before and I remember getting if fixed but couldn't remember what the problem was. I think it was the wippen flange being too tight!

    ------------------------------
    "That Tuning Guy"
    Scott Kerns
    www.thattuningguy.com
    Tunic OnlyPure, TuneLab & Easy Piano Tuner user
    ------------------------------

    Original Message


  • 5.  RE: jack issues

    Registered Piano Technician
    Posted 01-18-2018 18:26
    I'm not familiar with the C-108. What's the wippen flange friction now (after the CPL has flashed off)? How tight is the balance rail hole? If tight, ream to proper depth, ease if necessary. Key pins polished, lubricated if necessary? Key bushing friction to spec? And Wim's diagnosis about the damper lift felt/spoon condition applies as well.
    Good luck!

    ------------------------------
    Patrick Draine
    Billerica MA
    978-663-9690
    ------------------------------

    Original Message


  • 6.  RE: jack issues

    Registered Piano Technician
    Posted 01-18-2018 19:59
    Hi Sheffey.  If you have issues with Jack, then perhaps you should speak with Jack directly.

    The C108 is a short keyed piano.  When you remove the action I'd bet the keys all go down to the depressed position.  I like all the suggestions so far but quite frankly, time is money.  Pursue excess friction meticulously and then add a lead weight on the back of the key.  Check the key with out the action to make sure it moves freely. Maybe even check it's backweight and compare it with the others.  Remove the whippen and check the flange for tightness.  Check the damper lever flange and check for tightness.  Check the contour of the damper lifter felt and the position of the spoon.  A deformed spoon can dig in the felts and eventually cause problems.  If nothing is found, add a lead to the back of the key and be done with the problem.

    ------------------------------
    Larry Fisher
    Owner, Chief Grunt, Head Hosehead
    Vancouver WA
    360-256-2999
    ------------------------------

    Original Message


  • 7.  RE: jack issues

    Posted 01-18-2018 20:07
    I've seen spoons bent incorrectly in such a way that the top was cutting the damper felt and carving a hole. It left felt powder to be easily seen.
    -chris



    Original Message


  • 8.  RE: jack issues

    Registered Piano Technician
    Posted 01-18-2018 20:16
    Whippen cushion felt may have big divot from the capstan, with more friction than when new. Or capstan has sharp edges digging into the felt.

    Paul McCloud
    San DIego


    This is a 1987 Yamaha model C-108. On A3, and so some degree, A4, the jack fails to reset, but Only when the damper pedal is down. I can play it rapidly without issue when the damper pedal is Not used. Other keys work just fine. So, 1st I put a little CLP on the jack flange - no diff. The regulation is good, there is no corrosion on the spoon, the key is not binding.
    Eventually I did the following:
    strengthened the jack spring
    repinned the jack flanges
    tried giving the key more lost motion [lowered the capstan]
    tried raising the hammer rail
    lubed the wippen flange
    put some CLP on the buttskin [why not, at this point?]
    Nothing helped. When the damper pedal is in use, Why are these two keys not getting enough energy to reset when everyone else is?

    ------------------------------
    Sheffey Gregory, RPT
    [



    Original Message


  • 9.  RE: jack issues

    Registered Piano Technician
    Posted 01-19-2018 22:51
    I had a similar problem with a spinet, and after trying everything I could think of, "fixed" the issue by putting a binder clip on a sticker near the elbow. The owner didn't want to spend a dime more on trying to solve it in a more conventional manner (and this piano definitely wasn't worth spending any more on...).

    Some time later, I asked a well-known tech about it, and his suggestions were to both strengthen the jack spring and weaken the hammer spring.

    Any opinions on weakening the hammer spring to help the jack return?

    ------------------------------
    Scott Cole
    Talent OR
    541-601-9033
    ------------------------------

    Original Message


  • 10.  RE: jack issues

    Registered Piano Technician
    Posted 01-20-2018 10:51
    Roger, Patrick & Larry - the wippen flange friction is something I had Not looked at, and if tight, would be consistent with the problem and the solutions I have already tried.  I just never thought of the damper spring as a "wippen assist spring" :)  If the wippen flange is good, I'll add lead weights. I find it interesting that this happened on an "A"... for some reasons, far more than probability would dictate, more problems happen on "A"s and "C"s than other notes, in my experience.
    The is no divot in the damper lever felt or any sign of undue wear, I checked that when I checked the spoon, just didn't report separately on it. And even if there were, it would not be the solution because it would uniformly cause an issue. This issue Only happens when the damper pedal is engaged.
    Thank you all for responding. When I get back to the piano and test, I'll post results, to "close the loop".

    ------------------------------
    Sheffey Gregory, RPT
    [
    ------------------------------

    Original Message


  • 11.  RE: jack issues

    Registered Piano Technician
    Posted 01-20-2018 22:32
    The individual damper return springs help push on the damper lever.  The other end of the damper lever is pushing on the spoon which aids in helping the whippen return.  If the WF is tight, the whippen won't return on it's own.  Remove the key and work the whippen to "sense" for tightness.  This takes years of experience to detect so might as well remove the whip and check the flange the right way.



    Original Message


  • 12.  RE: jack issues

    Registered Piano Technician
    Posted 01-21-2018 02:14
    It might have been quicker to just check the upweight at the beginning.  If you find it to be in the low teens, you know you've got a problem and rather than tear apart the whole action looking for a sluggish flange, worn bushing, weak spring, etc. it would be simply more expedient to add a jiffy lead to the key behind the balance rail to restore the poor repetition.

    ------------------------------
    Cecil Snyder
    Torrance CA
    310-542-7108
    ------------------------------

    Original Message


  • 13.  RE: jack issues

    Registered Piano Technician
    Posted 01-31-2018 09:56
    I went back to the customer Friday.  The wippen flanges on A3 and A4 both tested out at 1 [one] gram in either direction.  So those two keys now have jiffy leads. Fixed a couple other minor issues and left the customer happily playing Bach.

    ------------------------------
    Sheffey Gregory, RPT
    ------------------------------

    Original Message


  • 14.  RE: jack issues

    Posted 01-31-2018 22:23
    😀 Way to go! 👍

    ------------------------------
    "That Tuning Guy"
    Scott Kerns
    www.thattuningguy.com
    Tunic OnlyPure, TuneLab & Easy Piano Tuner user
    ------------------------------

    Original Message