I also have one of these Electrone key top piano players which
plays well.  The design of the individual plastic "pneumatic+valve"
assembly very closely resembles that of 1920's Simplex player action
unit pneumatic.  This makes servicing weak or non-playing individual
notes less daunting.

The turbine vacuum motor is rather noisy.  It sounds like a jet
taking off when the unit is activated, but it powers the player quite
well with three vacuum level settings (low-medium-high).  Mine plays
best in the medium setting.

The Electrone has a manual knurled thumb screw tracking adjustment
that moves the tracker bar laterally.  It has automatic reroll,
but does not turn off automatically at the end of the reroll.  The
play-reroll operation is controlled by a sliding lever on the lower
right hand of the spool box.  A "neutral" center position of the
control lever allows the operator to load the piano roll, while the
rheostat-controlled electric roll motor continues to operate.

The Electrone plays standard 88-note rolls and will accommodate large
medley rolls too.  My unit was new old stock from an old local piano
store here in Savannah, Georgia, which I obtained in the 1970's from
the owner.  He had three of them sitting on a shelf in the back room.
They didn't play from lack of use.  I repaired them and found the
store owner buyers for two of them in return for my unit.

I think that they were manufactured in the early 1960's as they have
molded fiberglass cases, but there is no date on the inside that I can
see.  I doubt that they were big sellers as they are heavy and rather
cumbersome to move.

You have to be very careful not to scar the cheek blocks of the piano
when positioning the Electrone unit onto the keys.

Hope this helps.
David Oppenheim