[pianotech] Yamaha Puzzler

[Joseph Garrett]

All,
Well, there were only a few that chimed in on this one, And, no accurate
reasons/fixes. To refresh: When the Soft pedal was used, it caused many
notes to Sustain! Yikes! 
Cause was three-fold: 1. the pedal stop felt was compressed too much. 2.
The hammer rail stop felt was compressed excessively by the cast-in-the
action bracket node, allowing the rail to go way beyond 1/2 travel. 3. Most
of the damper spoons were adjusted to lift 1/3 of the way to the string,
(early). 
The fix(es): 1. Insert a Felt Bench Glide* on top of the existing pedal
stop felt, to restrict the depth of pedal travel. 2. adjust the damper
spoons to lift at half stroke. 3. Leave the bridle straps at their present
adjustmment to compensate, (somewhat), for the broken butt spring loops,
until client o.k.s that repair.
The second part of the puzzler was: There are several butt spring loops
broken, but the repetition does not seem to be affected. Why?
Reason(s): 1. The action geometry is set so that the hammer shank does not
go any where close to Vertical, (0 degrees). 2. The bridle straps are set
to engage slightly early,  causing the wippen mass to pull back the
hammers. 3. Dampers were set to lift early, putting the wippen/damper
spring energy into the "repetition" force.

*The self adhesive Bench Leg Glides, available at my local Ace Hardware, is
a MUST in my Kit! They can be used as spacers and stop felt for trapwork,
as well as getting you "points" with your clients that have nice hardwood
floors, etc. I install them as a free thing. They don't cost much and since
I move their bench around a lot in the tuning process, I don't want to be
doing damage to their floor. Pedal Mats are a good thing also.
That's my take on that. Have a good week.
Regards,
Joe


Joe Garrett, R.P.T.
Captain of the Tool Police
Squares R I