Paul Kratzer posted looking for a player mechanism for his Emerson
upright; now, a quick check of Player-Care shows four different player
mechanisms commonly fitted to Emerson uprights: Standard, Amphion,
Autopiano, and Angelus -- lotsa choices.
Then there is the piano's scaling: where is the bass/treble break
and the gaps for the plate in the treble? So, one needs quite a bit
of information to re-fit a player in a piano.
That's not to say it can't be done, but it's easier in, say, a Gulbransen
as they were mostly used in their own pianos (and yes, it's harder to
rebuild one!). A Simplex unit, by it's design, is easier to modify to
fit different scalings.
So, Paul, we need more info -- measure the piano action where the
player connects (usually at the top of the stickers) to get a layout
of the scale, and see if you have any other clues as to the make of
player, such as the controls layout.