The National Museum of Computing, Bletchley Park, UK, has a decent number in its collection. -- Colin N0body H0me <n0body.h0me at inbox.com> wrote: I have a few, some actually work! 11c - Purchased *new* the year it came out 16c - Replaced one that was *stolen* in 1986 41C (broke) 41CV (broken case) 45 - Purchased at TRW in 1985 97 - Thrift store find, c.1999 I used to have a 31E that I got when I went away to college in 1979. It had the best keypad of any calculator I ever owned, bar none. I also had a 35, but I dunno what happened to it. Jeff _____________________________________________ FREE 3D MARINE AQUARIUM SCREENSAVER - Watch dolphins, sharks & orcas on your desktop! Check it out at http://www.inbox.com/marineaquarium

On Mon, 5 Mar 2012, Eric Smith wrote: Have you seen the wp34s? See http://sourceforge.net/projects/wp34s/ -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

AFAIK that was the only RPN desktop calcualtor (the earlier 900 and 9810 machiens are sort-of stack based but IMHO since they lack auytomatic push and pop, they;'re not really RPN). It's also the only HP calculator (before the HP9000/200 seires) that used a standard CPU chip (there's a 6800 in there). Most models are not rare, but there are quite a number of people who like them, so they can sell for failry high prices. -tony

I absolutely ageee. The HP9100 is one of the most elegant devices it's ever bene my pleaser to work on. It is truely beautiful. Incidentally, the 9800 series machines are one of the few bit-seiral TTL-based desktops you're likely to find. They too are quite elegant inside, albeit using TTL chips not discrete transistros. IMHO they are a lot easier to repari than the 9100 (I've done both), and certainly a lot easier to itnerface. -tony

Assumnign it was an HP9800 family machine, there are 4 possiblities : HP9810. 3-reigster pstifix machine (not strictly RPN IMHO, in that the 'stack' doesn't operate at all as you'd expect). The display is 3 lines of digits, 7 segment LED. There's a built-in magnetic card reader and an optional internal thermal printer HP9280. This uses an algebraic notation (infix), but is still a programable calculator. The display is 16 character alphanumeric 97*5 LED dot matrix), again the same card reader and printer as the HP9810 (I think the printer awas standard, not an option). HP9821. Essentially an HP9820 with a digital cassette drive rather than a card reader. This is by far the rarest of the family. HP9830. Physically larger. It has no internal printer (but an HP9866A thermal printer is desiged to stack on top of it). There's a built-in digital cassette drive. The display is 32 character alphanumeric, the keyboards is a nromal QWERTY layout, rather htan the numeric keypad and symbols forund on the other machines. It prorgams in BASIC. Othe good sties to look at are http://www.hpmusuem.org http://www.hpmuseum.net (lots of manuals to download in .pdf format). The price has shot up recently, I suspect yuou're looking at $500 to $1000 for a reasoanble one. It's unlikely to still be working, but they are repairable (most of the logic are common-ish TTL chips. There are custom firmware ROMs, of course (and they are not pin opr fucntion compatible with any normal EPROM), and the RAMs are 1103s which are not easy to find now. Possibly an HP2100A? -tony