[ At the end of email 060414 MMDigest (not archived):
> At eBay auction: "Auto Electric Piano Co.", 44-note, electric reader
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7407165526

This dandy little gem is solenoid operated.  In one picture you see
a board with the contact wires for the tracker, hence no vacuum pump
or electric motor.  It would be neat to know more about this rare piano.
I have never seen nor heard of a roll for this model.  There were also
models sold that used the vacuum system.

Good luck to the lucky winner of that piano and I hope you share some
better photos with the rest of us.

Don Teach