Steinway upright sostenuto

[CDeets@aol.com]

Dear List:

I need to do some regulation work on a Steinway upright.  The sostenuto does
not work quite right, (it holds some dampers but not all) and another
technician told my friend that it could not be fixed (I think he didn't know
how to fix it, or didn't want to bother).  I assume that it works like a grand
sostenuto, but I haven't been able to find literature or reading on the
matter, in either my Potter course manual or the Reblitz.

Does anyone have the regulation sequence for a Steinway upright?  Specifically
on the Steinway sostenuto?  I will gladly pay for postage and copying if
someone has it handy.  I have regulated umpteen verticals, but never one with
the sostenuto mechanism.  

Sincerely,
Craig Deets

Associate member, Chicago