Yamaha P1 backrail "cloth"

[Jim]

On Sat, 7 Sep 1996 Wimblees@aol.com wrote:

> Dear List:
>
> Today I ran accross a problem I have never witnessed. I tuned a 35 - 40 year
> old Yamaha P1 with very bad lost motion. I started adjusting the capstans,
> but the first key I did wound up blocking the hammer against the string. I
> then noticed that under the back of the  keys, where the back rail cloth is
> supposed to be, was some gooie (sp) material, with the consistency of peanut
> butter, only a little more solid. I could scape this stuff off the wood with
> my fingers.  My recommendation to the customer was to replace this stuff with
> regular back rail cloth.
>
> First of all, can anyone tell me what this stuff is. And second, does anyone
> know what thickness of cloth I need to use.
>
> Willem Blees  RPT
> St. Louis
>

Dear Wim:

The gooey material may have been melted sponge rubber which was tried by
various manufacturers back in those days.

If you haven't already run up all of the capstans, a good procedure is to
select a backrail cloth which raises the majority of the capstans to the
point of minimum lost motion, as long as you still will have fairly normal
keydip.  This will minimize your regulation work and is probably as close
to the original as you can get.  Be sure that you will still have suffi-
cient keydip.  You wouldn't want the key overlip to clack on the keyslip,
and you wouldn't want the back of the sharps keysticks to be limited
by the normal position of the nameboard or keystop rail.

Jim Coleman, Sr.