I am presently finishing off the full restoration of my Weber Model
12 Pedal Electric Duo-Art (PEDA) grand piano.  Having taken the piano
action out and just started work on it, it has proved rather puzzling!

The Model 12 has a upper player action which rests between the
wrestplank and the keys, therefore a special action was designed to
allow the mechanical actions push rods to act on the grand lever.  The
action has another lever -- a compensation lever which has a spring so
that you can adjust the weight of the pianos action.  This is adjusted
at the back of this lever with a small grub screw.  This lever also has
the back check on it instead of on the back of the keys.

While adjusting the action is complex, articles have been written on
how to do it.  The recognised way is to weigh the action with a spring
balance which is connected to the felt pad which the pneumatics lift.
If done properly, an even weight can be produced from bass to treble,
or in fact a slow graduation.

The problem is, at the back of the compensation lever you have the back
check, then a wooden pad that is used to lift the dampers.  Behind that
there is the grub screw to adjust the compensation spring and finally
another grub screw that screws up and down a brass button.  The brass
button is underneath all of the compensation levers from treble to
bass.  There seems to be no rod, bar or in fact anything in the piano
which these buttons would in fact work on.

These actions were made for Aeolian/Weber by a number of manufacturers.
Many seem to have Herrburger Brooks actions but mine is illegible and
is certainly not them.  It was made in Leipzig and the firm has two
names with an ampersand (&) in-between.

Any suggestions what these brass buttons are for would be appreciated.
I have photos of the action and lever and the inside of the piano,
i.e., the keybed, which I can send out.

One suggestion was it was to do with the dampers, but this is not
the case.

Kind regards,
Jonathan Holmes
Penzance, UK