• 1.  U1 practice mute issues

    Registered Piano Technician
    Posted 12-06-2022 00:56
    Hi all,
    I've adjusted many practice mute systems, but I ran into one today that stumped me. It's a 1980 U1.
    The customer reported a key was stuck down, and I saw some hammers were getting stuck on the mute felt.

    Easy, right? Just crank up the turnbuckle enough so the felt clears the hammers? Nope.

    When I had the felt just clearing the hammers, two things would happen:
    1. The mute felt now wouldn't go low enough to have any effect and
    2. The turnbuckle rods were getting so loose I was afraid the whole thing would start to rattle under normal playing.

    A little trimming of felt or some adjustment has always did the trick, but something else is wrong here. I'm just not sure what.

    Anyone else had problems getting these adjusted just right? I've worked on a bazillion of these things and never had a problem.

    Scott Cole, RPT
    Talent, OR

  • 2.  RE: U1 practice mute issues

    Registered Piano Technician
    Posted 12-06-2022 02:38
    Hi Scott:
    You have to analyze the whole system, like the relationship between the key dip and blow distance.  If the pedal doesn't move down far enough, there won't be enough movement/travel of the rail. 
    See if the linkage to the pedal is in the same hole as when it was new.  If the pedal was replaced at some point, maybe they connected the linkage to a hole closer to the pedal pivot, and that would limit how far the linkage moves when you press the pedal.
    Some Yamahas have different lengths of their side brackets, and they put the pedal linkage connection closer to the pivot point, which allows the rail to travel farther down for a given "pedal dip".  More angular motion with the attachment point closer to the pivot.  Try to find a way to move the linkage wire attachment point closer to the pivot so it will move farther.  Most Yamahas are pretty good and the mute rail usually has plenty of movement up and down.  Something is amiss.
    Also, look at the attachment of the mute rail to the left side bracket.  Make sure that they fit together as designed and are not tightened at an angle.  You may want to remove the rail and tighten all the bracket screws to the rail.  There is usually a small hole in the bracket and corresponding "pin" in the rail that keep the rail and the bracket in the proper position when you tighten the screw. 
    Look at the attachment to the linkage where it connects to the bracket.  Is it bent somehow so that it limits the travel of the rail? 
    Are there extra holes where the pivots attach to the inside of the case?  Perhaps someone drilled new ones in an attempt to correct the situation, then later someone put it back in the old holes.  You get my drift. 
    Look at everything in the linkage to see if something wore out, broke off, got loose, etc.  Also, check the spring that lifts the rail.  If it's too weak, it won't hold up the rail properly when it's in the "off" position.  You might have to drill a new hole for the screw-eye to increase the spring tension.
    Has the felt been trimmed excessively?  Has it been replaced? 
    Is there some felt block glued under the pedal to keep it from making a metallic noise that might be limiting the pedal movement?  Is the pedal bracket loose?  All sorts of things can happen in an old piano that are not immediately obvious to cause problems like this.  A spring under the pedal that helps lift it might be broken and you can't see it because it's hidden under the pedal.
    I've had to advise the client that I can't fix or adjust it, so they might just get used to not using it.  Aka, I give up!
    Good luck.

    Paul McCloud, RPT
    Accutone Piano Service

  • 3.  RE: U1 practice mute issues

    Registered Piano Technician
    Posted 12-08-2022 00:47
    I have found that this condition is the result of the mute rail being positioned too far from the strings. Gently bow the rail toward the strings and you should be able to adjust it properly.

    Ted Kidwell, RPT
    California State University, Sacramento
    Capistrano Hall, rm. 153
    6000 J Street
    Sacramento, CA 95819-6015

  • 4.  RE: U1 practice mute issues

    Registered Piano Technician
    Posted 12-07-2022 00:26
    Hi Scott,

    I just ran into the same problem last month, but it was on an older Yamaha M-series. It baffled me for a while until I realized that the bottom board was bowing a bit in the center, right under the pedals. It would be fine until you depress the damper pedal, then the hammers would catch on the soft rail felt. The extra pressure from one’s foot on the damper pedal was enough to drag down the middle pedal assembly enough to cause the felt to be just low enough to cause problems.

    I tried raising the soft rail felt considerably, but it ended up being too high to drop between the hammers and strings when you engaged the middle pedal. Ended up having to shave about 1/8” off the felt for it not to catch.

    The other option would have been to repair or replace the bottom board, but that wasn’t feasible in my case.

    I don’t know if this is what you’re facing or not, but it was the first time I’ve seen that. Hope it helps,

    Benjamin Sanchez, RPT
    Piano Technician / Artisan
    (256) 947-9999