In addition to collect HP calculators I decided to collect calculators made in my country Argentina. Of these I have models of the brands: microcifra, Magiclick and Norman.
Yesterday I buyed a "new" one: "microcifra 10" a scientific model that operates what I think is true RPN. It has an [E] (enter) key. It has a stack that can have up to 3 levels, a [x<>y] key and two erase keys:
[C] that acts as "drop": if you enter [1],[E],[2],[E],[3],[C] then you have only two levels ("2" is displayed) and if you press [C] again you have only one level ("1" is displayed).
[C*] erases all the stack. Then all you have is "0" in the first level (and the other two levels doesn´t exist). It also clear the memory register.
The calculator operates on 6 AA bateries and have a 8 digit led display.
You can see it in my site:
http://ar.geocities.com/casta1967/calculadoras/coleccion/calc43.htm
I don´t know if this could be interesting in this forum but I couldn´t resist to share.
Regards,
Guillermo