I have a similar, but not identical, music box, called the "Melodean"
(sic).  It's Japanese, and I bought it in the late 1960s as a Christmas
gift for my father.  I paid $20, if I recall right, from a San Francisco
mail-order shop called Haverhills.  It came with some pre-punched tunes
and about three blank cards, one of which I punched with my arrangement
of an Old World dance tune that my Dad loved to play on the piano.  He
was really tickled!

It runs on three size "D" cells and has a rheostat knob to vary the
tempo, whereas others are reporting hand-cranked units.  The motor
starts automatically when you shove the card strip into its mouth on
the side, and as it plays the card loops back and is ejected out the
bottom.  It looks like a small fake-wood table radio of the transition
era from tubes to transistors.

The scale is indeed 20 notes, diatonic from C up to A.  The lever
plucker action is simple but effective and reliable, and the tone is
very solid and clean, although I wouldn't trade my Reginaphone. :-)

I've been meaning to write up a short article on the Melodean for one
of the MBSI publications, having never heard of such a box anywhere
else -- until now.

Mike Knudsen