Pianotech

Expand all | Collapse all

Croaking Sustain System

  • 1.  Croaking Sustain System

    Posted 05-27-2019 09:13
    I have a client who has a 20 or 30-year-old Conn console. Not a great piano originally, but in excellent condition. Except for the darn frog that croaks every time you release the sustain pedal.
     
    I'm trying to figure out what the cause is. As often the case, the cause seems to be elusive.
     
    It's not the pedal itself - clearly, the noise is up at the action level - no mistake about that.
     
    It's not the rod - I flipped it 180 degree and same croak. I even swapped out the pseudo-sostenuto rod with the sustain rod and same croak. I installed new felt and rubber ends on the sustain trap rod - same croak.
     
    I lubed all the damper lifter rod action centers with Protek. That seemed to make the frog go away for a few days, but then it returned.
     
    The croak sounds like it is coming from the far treble end of the action.
     
    I replaced the treble-most damper lift rod action center - same croak.
     
    I am looking for ideas on what else it could be.
     
    Probably one or more of the other damper lift rod action centers???
     
    I'm thinking that the next step should be to replace all six damper lift rod centers, polish the damper lift rod and to brush micro-fine teflon power on all the damper lift felts (the felt on the lower part of each damper lever).
     
    What else could possibly cause the croak? The damper springs? The damper action centers? Those are the only other moving parts - right? I don't think it really could be either of these latter items. What else?
     
    Thanks for any thoughts.


    ------------------------------
    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
    ------------------------------


  • 2.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-27-2019 09:26
    Check to see if the wooden rail is split at the end. 

    Gary Bruce
    Registered Piano Technician





  • 3.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-29-2019 01:17
    Use a stethoscope to zero in on the frog.

    ------------------------------
    Cyrus Welch
    Sacramento CA
    916-205-4487
    ------------------------------



  • 4.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-29-2019 05:04
    Terry
    Check the base of the action frame fit to the piano.  Even though the action holding  nuts are secured,  any slack where the action meets the piano, the same noise can occur. Simply raise the capstan-type adjuster bolt at the base of the action frame and see if that's culprit. Happy hunting....

    ------------------------------
    Tom Servinsky
    ------------------------------



  • 5.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-29-2019 08:40
    Mr. Farrell,
    You might have a case of right spot wrong lube. I've had that same groan from the damper lift system hanger centers on both grands and verticals. I have found that a dry film or dry powder (teflon,mica,or talc) worked better than an "oil" type lubricant. A film type like mclube is easy to apply to the hangers while the powder type needs the little hanger brackets to come off the frame to get it inside the bushing. In your situation with the protek already in the felt I'd use talc for it's bigger grit to try and mitigate the oil on felt squeak effect.

    ------------------------------
    Karl Roeder
    Pompano Beach FL
    ------------------------------



  • 6.  RE: Croaking Sustain System

    Posted 05-27-2019 09:29
    I've had this same thing on old BOU's. I think your are going to find it in the damper lift centers, as you mentioned. I'd change them all out. Also, once, for me, there was one screw which attached the damper lift center bracket to the rail that was ever so slightly loose...not really loose...but just enough to cause the noise. 

    Like chasing ghosts sometimes...

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 7.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-27-2019 10:47
    Terry,

    Are the action brackets secure? They could be rubbing on the bottom bolts

    Paul

    ------------------------------
    Paul Brown, RPT
    President
    Piano Technicians Guild
    Vancouver, BC Canada
    Email: pres@ptg.org
    ------------------------------



  • 8.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-27-2019 10:48
    Terrence,
    I would guess it is nearly a 100% chance that the action post (the post that is screwed into the keybed that the action sets on) is not tight against the action frame. Remove a few keys next to the end action post and turn the post upward with a wrench until the groan stops.
    Roger





  • 9.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-27-2019 14:31
    I agree with Roger and Paul.  But before turning the bolt, which will change the action geometry, put some VJ lube on the post.  And/or a then piece of action cloth.

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



  • 10.  RE: Croaking Sustain System

    Posted 05-27-2019 12:51
    Damper springs in slot/felt punching taco. Crusty lifter felt on levers contacting the rod. Is the sound there if you press on the stretcher at the pedal with your foot; if the noise is there, it's the bottom board.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
    ------------------------------



  • 11.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-27-2019 22:13
    Could it be a loose bottom board?

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



  • 12.  RE: Croaking Sustain System

    Posted 05-28-2019 05:39
    I'm quite sure it is not the bottom board. I do realize that sometimes where the apparent location of a noise can be difficult to ascertain, here it seems so very clear that the noise is up at the action and also, there is like zero flex in the bottom board and entire lower pedal system. It's up at the action level, I'm quite sure.

    ------------------------------
    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
    ------------------------------



  • 13.  RE: Croaking Sustain System

    Posted 05-28-2019 08:43
    Have you tried reproducing the noise with the action out on a table?

    ------------------------------
    Jim Ialeggio
    grandpianosolutions.com
    Shirley, MA
    978 425-9026
    ------------------------------



  • 14.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-28-2019 08:46
    There may be one or two damper levers that are not assigned to a note that have stiff springs on them to help in the return of the rail.  It could be one of those.
    Gary Bruce


    CLICK HERE to schedule your next piano tuning.

    405-413-8863 (cell)







  • 15.  RE: Croaking Sustain System

    Posted 05-28-2019 10:28
    Jim I wrote: "Have you tried reproducing the noise with the action out on a table?"

    Yes I have, and it does not make the noise. Whereas that could lead to the logical conclusion that the noise does not come from the action, I suspect that one simply cannot perfectly replicate all the exact strains and stresses in that manner. Obviously, I could be wrong....  :-(

    ------------------------------
    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
    ------------------------------



  • 16.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-28-2019 13:05
    Terry, in your original post you wrote:
    "I lubed all the damper lifter rod action centers with Protek. That seemed to make the frog go away for a few days, but then it returned."

    I suggest you repeat that experiment, going through all the same component manipulations (remove/replace/wiggle, etc) but without additional lube.  See if you get any relief.  Then go through same procedure but with lube -- perhaps applying lube to only one center at a time.

    My thinking is that, of all the things you tried, this was the *only* one which produced good results.  That suggests the cause lies in those action center bushings or mountings.

    Good luck!

    ------------------------------
    John Rhodes
    Vancouver WA
    360-721-0728
    ------------------------------



  • 17.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-28-2019 13:44
    John,
    Good observation. Assuming the action was removed to lube the hangers, it could have cleared up the action post/action bracket problem temporarily until the connection settled back into its original position and consequently the groan returned.
    Roger





  • 18.  RE: Croaking Sustain System

    Posted 05-28-2019 14:36
    Roger Gable suggested to look at the action posts/brackets. This action fits very snuggly between the action bolts from the keybed and the action retention bolts where the top of the action brackets attach. One actually has to apply a good bit of upwards pressure on the upper bolts and tap (hammer) the action back in place. It is a VERY tight fit (too tight IMHO).

    ------------------------------
    Terry Farrell
    Farrell Piano Service, Inc.
    Brandon, Florida
    terry@farrellpiano.com
    813-684-3505
    ------------------------------



  • 19.  RE: Croaking Sustain System

    Member
    Posted 05-29-2019 09:17
    Go to Harbor Freight Tools and purchase an electronic stethescope. It comes with different length probes you attach to the main electronic unit and is extremely sensitive. There certainly is a lube/felt connection plus glues and felt crustiness that can make noises. What have you done with the trapworks ? The bottom board may be sound but the noise may be coming from the pedals and the pedal pins and bushings, screws holding the pedal assembly down into the bottom board, the pedal adjustment screw for lost motion, the trapwork levers, springs in the trapworks or coils.
    There is a lot of stress and strain in the pedal/action connection that can be transmitted up the line but make you think it is in the action. Also tightening any and all screws in the action that hold brackets and rails in place . Post some pictures if you can so things can be better visualized.
    Are there any plastic pieces in the trapworks or the brackets the pedals rotate in ? I have seen a number of pianos in which the plastic bushings
    have cracked and the plastic cups under coils/springs split causing groans/squeaks/rubbing noise.

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



  • 20.  RE: Croaking Sustain System

    Posted 05-29-2019 10:23
    If it has a polyester finish, parts with the finish rubbing together will groan. Keybed?

    A plain old stethoscope will help isolate the noise, no need for a battery-powered device.
    I have one with a section of player tubing attached to the end for length. It's great for tracking down air leaks anyway.

    ------------------------------
    Regards,

    Jon Page
    mailto:jonpage@pianocapecod.com
    http://www.pianocapecod.com
    ------------------------------



  • 21.  RE: Croaking Sustain System

    Registered Piano Technician
    Posted 05-29-2019 15:46
    Is this an Asian-made instrument? If it's an older American, another possibility to add to the list would be the pedal lever springs, either loose or cracked.

    Plan B would be to convince the client that sustain pedals are over rated anyway.

    ------------------------------
    Steven Rosenthal
    Honolulu HI
    808-521-7129
    ------------------------------