Story and Clark/QRS console bubbling hammers

[Piannaman@aol.com]

---------------------- multipart/alternative attachment
Hello again,

It's been a week for pain-in-the-posterior piano problems.  A couple of 
months ago, I was called to come and see if I could figure out and fix a problem 
with bubbling hammers on a Story and Clark console piano with QRS pianomation 
installed.  When I got there, almost every hammer was bubbling.  Key height was 
fine, but the dip was way to shallow.  I replaced the fat front rail felt 
punchings with more meager ones, did a bit of regulation, and the problem was 
gone...at least for the time being.

I got a call from the lady a couple of weeks ago complaining of a few more 
bubbling hammers.  I got a chance to go out yesterday, and with a small amount 
of let-off adjustment on a few notes the problem seemed to be cured--until I 
pushed the sustain pedal down.  I could not make all of the hammers check when 
the sustain pedal was engaged.

Can anyone tell me if there is some connection between pedal/damper function 
and the QRS mechanism?  It doesn't seem as though there should be, but I have 
never installed or worked on one of these.

The problem seems to be that when the sustain pedal is down and the dampers 
up, there is not enough strength in the springs to push the hammers back 
quickly enough to catch on the backchecks.  

My thought is to check the tightness of the whippen and hammer centers.  The 
action feels far more sluggish than it did the first time I worked on it.  I 
suspect moisture or something else has invaded the bushings.  Maybe graphite 
coated center pins???  I certainly hope not.  Been there before.

Any thoughts or recommendations for possible courses of action would be 
appreciated.

Thanks again!

Dave Stahl

---------------------- multipart/alternative attachment
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/27/a3/21/af/attachment.htm

---------------------- multipart/alternative attachment--