I have restored many of these toy piano units.  The snail cams on all
of them were bad.  To restore them, I machined a new cam for the first
unit I restored.  I then had bronze castings made of that snail cam for
the other units I restored.  I can supply these cams as machined parts,
It is however better if I fit the part to the piano, they are
different.

For further information on my efforts on this toy piano see my entries
in the MMD Archives subject index, "Verbena by Reig".

Gary G. Stevenson
South St. Louis Mo.
http://pages.prodigy.net/studio801/