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Hp-15c Gone, but not forgotten

  1. Feb 18, 2010 #1
    I'm sure any number of us have fond memories of the hp-15c and hp-11c calculators. There's even a web site where throwbacks like myself complain to the hp people to bring it back, but considering one server room represents more business than all the calculators they could ever sell, it occurs to me - is it realistic to build replicas?

    As I understand the situation, people have the code and it's floating about on the internet. Does this sound like a good time for the old timers, or an open invitation to dunk our retirement in lawsuits?

    - Mike
  2. jcsd
  3. Feb 18, 2010 #2
    Do you feel like to rebuild it using new component
  4. Feb 18, 2010 #3
    If either of you are/were HP employees, you can answer my questions. In the mid-1950's while I was in college, I worked part time for Bernie Oliver in the (only) HP plant on the SW corner of Page Mill and Park Blvd. in Palo Alto. A few years ago, someone told me Bernie was involved in developing the HP-35. Is that true? Second, when I was there, HP was profit sharing. I never got my last profit sharing (in 1958). Do I have any profit sharing due me?

    Bob S
  5. Feb 18, 2010 #4


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    If HP brought back the 15C, I'd buy one in a heartbeat. Good size, good key-pad feel, nice display AND RPN. At the time the 15C came out, I already had a 21C that filled my needs, but I'd certainly like to have one now.
  6. Feb 18, 2010 #5
    The Accounting guys still have a calculator that's the same form factor as the 15c. Swap the keys (not the buttons!!!), drop in a different processor, and change the logo.

    Presto, 15c.
  7. Feb 18, 2010 #6
    15C was my first HP, bought off a small scholarship my freshman year. i still have the calculator and the book.
  8. Feb 18, 2010 #7
    You guys are joking right? Why would you ever want one of these things when there are modern calculators out there that are so much better?
  9. Feb 18, 2010 #8
    I had an HP15c back in college and it got me through my undergrad years 82-86. Then a friend bought me an HP28s. I liked it better because of the bigger stack and easier matrix and complex math entry. I used this from 1986 till now. Ten years ago someone gave me another HP28s, so now I have two. These are both about 25 years old and work like new. The batteries (although they are the hard to find N batteries) last me years at a time.

    This year, someone on a forum mailed me an HP49G for free. It's very impressive, but for doing simple math, I prefer the HP-28s, and for complicated math (symbolics, programming, etc.), I'd just as soon use a computer (Maxima, Matlab etc). The batteries die in weeks of use and the keyboard entry is very unreliable.

    My point is that the modern calculators are only better from a certain point of view, and I can understand why people might prefer the old. Although I prefer the HP28s to the HP15c, the preference is very marginal and based on matrix and complex math which I do rarely on a calculator (Matlab is much better for that).

    I just realized that the 3 HP calculators I have were given to me for free. I guess I'm very lucky. I did give my HP15c to someone in 1986. So, someone else was lucky too. I'll bet it still works fine.
    Last edited: Feb 18, 2010
  10. Feb 18, 2010 #9
    best thing 15C has going for it is a nice rugged case. if you could repackage it for about $10, it would be great for that type of calculator you keep in a drawer or glove compartment. it needs a new battery, tho. heck, slap your company logo on the thing and give them away as advertising swag instead of those POS solar gizmos.
  11. Feb 18, 2010 #10
    Bernie was a good friend of Hewlett and Packard. Did you ever see them around the shop?

    According to HP Website

    In the HP Journal June 1972 there is no mention of Barney. But they mentioned some engineers that were involved in the design of the HP 35.
    Last edited: Feb 18, 2010
  12. Feb 20, 2010 #11
    Why would anyone want a calculator that doesn't hide away easily in you slacks pocket? If you want to process data, flip matrices, or generate graphs, a pocket calculator is too tedious in any case. That's what PCs are for. It's better that a calculator be something small and robust - the very definition of the 15c.
    Besides, the public has spoken on Ebay. 15c's regulalry go for more than these "graphing calculators"
  13. Feb 20, 2010 #12
    I worked for Bernie Oliver 1954-58 part time when I was a student at a local university. I remember building a 6AM4 grounded-grid 420-MHz amplifier. HP was just two connected buildings then, so both Hewlett and Packard were often in the back building with the troops.

    Bob S
  14. Feb 21, 2010 #13
    That's amazing. This was the time when HP was undergoing a huge growth. I'm also familiar with Art Fong who led alot of RF/microwave designs. For a time I had HP 3200B oscillator 10-500 MHz based on tubes but I sold it on ebay.
  15. Feb 22, 2010 #14
    I worked on the Model 708 20-MHz to 420-MHz (vacuum tube) signal generator. I had a model 410 VTVM (vacuum tube volt meter) ser. No. 7, but my brother sold it when I was a post doc in Cambridge, Mass. :(

    Bob S
  16. Feb 22, 2010 #15
    Was is the 608? There was a whole fleet of these signal generators covering frequencies from VHF all the way up to 22 GHz.

    ser No. 7? oh man, that would be a rare item today, and sought by collectors.
  17. Feb 22, 2010 #16
    The HP model 608 was a 20 megacycle to 480 Mc (megacycle) vacuum tube signal generator, in production before 1954. It was perhaps 15" high, and had a big crank on it to change the size of the oscillator resonant cavity. See photo.

    The model 410 VTVM was a used bench unit at HP; they sold bench units to employees once or twice per year. I paid $3.00 (not a typo) for it.

    Bob S

    Attached Files:

  18. Feb 22, 2010 #17
    That's a fine signal generator and certainly served its purpose. It would make a great restoration project. I've stumbled on it before when I was looking for a microwave signal generator. I've eventually settled for YIG plug-in series, but got to know most of HP lines of signal generators in the process.

    The Bama Website hosts a free service manual with schematics for it, and many other of these generators.

    The 3200B I had wasn't based on a cavity, it had a combination of switched capacitor and inductor bank, and was tuned with a variable capacitor vernier. But the output was attenuated by some kind of a waveguide. It had a pick up coil in a tube that was inserted in the attenuator. The attenuation depended on far the tube is inserted.

    That's the HP way at work.
  19. Apr 18, 2010 #18
    HP has a 15c emulator for the iPhone. It is either $29 or $39, but that is way cheaper than what they go for on ebay.

    I'd buy more than one 15c, 32sII or 42S if they were ever reintroduced.
  20. Apr 18, 2010 #19


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    I'd snap up a couple of 15Cs in a heart-beat. My cell doesn't take pictures or run apps - it only makes phone calls. It accepts txt messages too, but I never tell anybody my number if they are the type to txt all day. They can call if they want to talk.
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