Unobtainium or Neverexistedium ?

While browsing the MoHP CDs, I remarked in the preface of the PPC ROM User's Manual (not a "guide" !!) that the author had a chance to play a bit with a prototype EPROM version of National Semiconductor's never released NS7100.
Sure this machine must be very very rare, as all unreleased models.
So comes up the question : which is the rarest ? The top contenders must be the HP95C, the TI88 and the NS7100. I think this is the right order from "most common" (!) to the rarest.
Does anyone have EVER seen an NS7100 ? Never heard of such an encounter.
V.Thoth has a TI88, the only publicly advertised ever. Probably less than a dozen of these leaked from TI. If I recall correctly from posts here the HP95C is in the less-than-100 league.
Do you know other such very-very-hard-to-find models ?


I suggest you switch the order of the 95c with the Ti-88.

My thoughts, the Ti-88 made it to store shelves, to be immediately pulled. Therefore, there must be more of them, but these very Ti calculators were pulled because of failure rates and poor life history. Therefore, most probably did make it back to Ti, but even a small % would probably be higher than a 100. Now how they were treated by their owners??? "$#%^& Ti doesn't work!! I'll throw this piece of $%^& right in the Garbage and buy an HP!"

Well maybe anyway.


I have been searching for an M55 calculator for years. Have yet to see one on ebay.

Anyone have one for sale? :-)


As long as we're talking about "unobtainable" calcs...
I'd love to have a TI SR60 (-A?) desktop calc. I'd love to have an HP91 desk calc, and I'd like to have a few Casio CFX20 and CFX200 sci. calculator watches !

Bill Wiese
San Jose, CA


There was one of these on ebay...closed today or yesterday.



I'm not such an equipment collector, instead I search for technology and information. Mostly because technology and information, once disclosed, remain with the keepr and may spread around everywhere without "fading", instead it is reinforced.

Anyway, I thik the most recently come-to-be-rare piece of technology is the Xpander. It is very well known and documented, also those who posess one of it will keep them with another perspective.

I compare all of them, HP95C, TI88, Xpander and now the NS7100 with each other, no way to try to reason about these "guys" as regular equipments that were never released. At the moment they become "Unobtainium or Neverexistedium", they go to another level of existence...(?)

I like more reading about them than reasoning about them. They are already history, and at this point, history cannot be changed. Also, I'd like to thanks to each one of those brave keepers who disclosed these dazzling, rare pieces of information I like so much to keep in mind.

My thoughts... Oh, I have 1ยข in my pocket!

Luiz C. Vieira - Brazil


I paid 10 bucks for a nice working SR60 at the Tucker Electronics in Dallas a few years back when they had their surplus store. One pops up on Ebay once or twice a year.

For the real exoitca freak, I snagged some TI calculators that were modified with different displays for market research studies. At the time TO only offered red LED's. These freaks had LCD, green LED, and orange displays. The machines were tossed in the TI trash, rescued by a scrounge, and sold for a pittance and the Dallas electronics sidewalk sale.


We want pictures !!!
... of the insides would be even better...
Thank you !

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