lost motion changing

[Roger Jolly]

Hi Frank,
         I recently assist a tech that had a similar problem. The fault
turned out to be caused by the two plate keybed shims being split from
either, over tightening or clumsy movers.
We made two new shims from some  bridge cap material and the piano now
appears very stable.
There are several post making sure the correct amount of lost motion is in
the soft pedal, but some other things to check are as follows.
1. Make sure that the screws are tight where the keybed is secured to the
arms.
Usually there is a minimum of 3 per side. if not this can cause the problem.
2. Check the plate to keybed mounting system to ensure there is stuctural
integrety.
3. Check the action/keybed nose bolts, there should be NO movement if you
try to wiggle the action brackets. If there is movement jack up the nose
bolts little by little untill the action is secure.

A few years ago I had an old upright that had no plate lugs to secure the
centre of the keybed and it showed the same symptom. I secured 48" long by
1 1/4" angle iron along the back of the keyframe with wood screws about
every 8"  The customer claims that there has been no problems with the
touch since the repair,
although I don't service this instrument.
Hope this helps, let us know what you find.
Roger  




At 10:33 PM 5/28/99 -0400, you wrote:
>Hello list,
>
>I recently regulated a very old upright...about 70 yrs old or so.  I
>went back today to check the tuning as per client's request.  Tuning was
>really ok, but a few unison's were out. 'Course the humidity is way up
>today and temps are in the 80's and all the windows were opened. But,
>she's a nice lady so to tweaked the unisons.No big deal.
>
>However, I noticed lots of lost motion everywhere. Can't figure out why.
>The capstans are quite loose and perhaps they worked themselves down.
>But the client is a beginer and uses the center of the piano. There was
>lost motion everywhere. I adjusted the lost motion in the middle third
>of the piano and will check it again soon to see if it changes. (didn't
>have time to adjust the whole piano)
>
>Any ideals what could have happened?  This has never happened before. 
>Is there any way to tighten up the capstans? (I can hear it now..."CA
>glue, Frank!") 
>
>This is so strange. 
>-- 
>
>Frank Cahill
>Associate Member, Piano Technicians Guild
>Northern Va
>
Roger Jolly
Balwin Yamaha Piano Centres.
Saskatoon/Regina.
Canada.