Backchecking problem

[Ed Guerra]

Hi Tom:  I seem to remember that some of the pianos at the university had
that problem.  What I found is that the repetition springs in the slots
were catching where the spring had made a groove and therefore not letting
the spring have much give.  

What I did at the time was to use a small screw driver and worked the
groove out.  You can use something else to rub out the slot.   Of course,
you know that you need to lubricate the slot again.  I also found that
protech is the best thing to  use.  

I hope that this helps.  



At 05:54 AM 6/12/98 -0500, you wrote:
>Dear list,
>
>I am stumped with the backchecks on this piano. The piano is an early 80s
>S&S L with new Premium blue hammers on Renner shanks & flanges and
>re-leathered original backchecks. I have CLOSELY regulated key height, dip,
>let-off and drop, spring tension, and all the other usual suspects. The
>problem is that the hammers absolutely refuse to check when the note is
>played at the level of forte or less. They just bounce between the
>backcheck and the string. The angle of the backchecks is good and they
>check high enough, but I just can't seem to get them to work in the piano.
>The problem is particularly bad in the bass and tenor, where the hammers
>are larger.
>
>The problem may be in the balancier. When I push the balanciers down, there
>seems to be much more spring resistance than normal although the hammer
>rise is not particularly fast. The original wippens have been rebuilt and
>repinned, so I'm pretty sure that it is a not pinning problem. The slots
>are clean and the springs have been cleaned and polished.
>
>I'm pretty much at my wit's end and if I don't get this resolved soon, I'm
>going to have to take a hostage. Any and all help will be gratefully
>appreciated.
>
>Many thanks.
>
>Tom
>
>Tom Seay
>Piano Tech Office
>School of Music
>The University of Texas at Austin
>t.seay@mail.utexas.edu
>
>
>
>
Ed Guerra
edguerra@mail.utexas.edu
Austin, TX