What is your holy grail?

I've got a decent sized collection of HP's, but there is always something elusive that you have to have, but can't find. For me it's a clear case 12c. I've got a few clear cases (28s, 19bii, 30b, 71b, 17b & 67), but a clear cased 12c would really complete my 12c part of my collection.

What is your holy grail? Cheers, Keith


Since I'm not a collector it's quite simple: the 41CL.

If I was a dedicated collector (admitedly I have a modest gathering of gear) I'd say a 41CY, or the slippery-elusive 3421 Control Module with soft-pad overlays... sigh.


A 34S with professionally labeled keys and faceplate directly from the plant. I presume this will never happen...


A 95C.


A mint HP-27


My missing brick it's an HP-92.
Not that I would discard a 95C... ;)



or the slippery-elusive 3421 Control Module with soft-pad overlays... sigh.
If it's just for a matter of collecting, that's one thing; but the 3421 definitely does not require the accompanying module in order to make full use of it.

For myself, I might say 41CL also, otherwise a Clonix-41, NoVRAM, or MLDL2000 or something like that. I'd like to see a concise comparison of them all. I expect the 41CL is the fastest, although few things are really so speed-critical

Edited: 1 Oct 2011, 3:08 p.m.


Probably either a 42s or 16c. I'm not equipped with the reckless abandon required to buy either of them, however.


My holy grail :-)


41CX S/N 2825S20268

Got me through college and then I sold it to a collector before I got the urge to start collecting myself. Would love to have it back ;-)



was wondering what a 41CY was, and upon searching chanced upon this series of photos that i thought others might like to have a browse over:


(sorry if this is a little off topic, but the photos are very well done)


I wish I had back ones that I no longer own due to failure:

- HP15c was my first, what I used in college until I broke it by (horrors) setting the foot of my chair on it, shattering the display.

- HP71b with card reader: just stopped working.

- H32s: bezzel around display was bent into display, I broke display trying to pry it up.

These were all done in my foolish younger years.

Glad I still have my 48sx w/eqn. library card, 35s, 50g and WP-34s...


Me too. I thought you already had one.


An HP 16C.


The finished version of Monte's 41CL.
A 34s-like unit with the screen of the new 17.
Eric's (and Richard's?) latest.


A few months ago, I would have said "A Texas Instruments SR-60", but now I have one.

These days...hmmm. Maybe a 9821, which was a 9820 with a cassette drive replacing the card reader.


With a 42S-esque case, white keys (grey for top two rows), yellow-f, blue-g, black-h, crystal, metal QR card on back, and serial port to the side.


A 34S with professionally labeled keys and faceplate directly from the plant. I presume this will never happen...

That would be great, but complete and proper documentation are needed first.

I like Egan's ideas as well.

Edited: 1 Oct 2011, 12:03 p.m.



Since you're in the area, you might think about attending CHIP meetings - we meet at Ace Metal in Bensenville. I expect to receive the 41CL in a few weeks which will go into my 41CX. This coming Wednesday (10/5) I will be giving a report on the San Diego conference, with lots of show and tell. Some of us get together for dinner at Two Chefs around 6:30pm, with the meeting starting around 8:00pm.

Edited: 1 Oct 2011, 12:17 p.m.


For me it would be a HP-67 CX. Was there any attempt to build one in the past ?




I've even seen one for sale or auction, have you?

Edited: 1 Oct 2011, 1:42 p.m.


Nope. Just the photos in the MoHPC.


As for a "collection" -- mine is mostly Voyagers. They're not particularly minty (except 15C LE, 12C AE, of course), but I like the ones I have. I mostly need to fill in on missing manuals (10C owner's handbook and the various advanced functions manuals).

But my holy grail is to be able to build my own calculator -- to gain the skills/tools in programming, part selection, PCB layout, case design/construction, etc., to make a calculator that does what I want.

I 'grew up' with an HP-25, but I like the continuous memory, the feel, the layout and the functions of the 11C, 15C, 16C. When I saw the 35S, I thought 'Great, HP is doing a CALCULATOR!' It's nice, but it's not a 15C.

I've also read here about folks wanting the 35S to have USB or SD Card, or some means of upload/download. I've read about the WP34S and using the tools for flashing a 20b or 30b (or 12C+ / AE or 15C LE). Got a 30b and a cable (thanks, Gene!) and will be loading it up over my vacation....

I read about the 41 series, including the blanknut.

I recently built my own sound-effects box (a display-less MP3 player with a LOUD speaker amp on board and files on an SD Card), so I've got a little bit of microcontroller programming and PCB design under my belt. Just a little.

So my RPN calculator is my next project.

I like the landscape layout of the Voyagers, and I look at my cellphone with a slide-out QWERTY (QWERTZ or AZERTY for some of you) keyboard.

If I were going to make a "blank" keyboard Voyager (or buy one, say a NW250AA#ABA OPT 001?), it would have the ENTER key horizontal (like my beloved HP-25) in the center of the bottom row, the spacebar position. Now I could use the keyboard / display of my "calculator" in an alpha mode for other things that need alpha input. And it would have USB and/or MicroSD, maybe a lithium-ion battery charged by the USB port. The holy grail of BYOC (build your own calc) hardware....

So I am following the discussions of the WP34S firmware with interest. Likewise the DIY5 hardware discussions, and the comments on various LCD displays. Thank you all for "teaching" me -- without really trying.

If I 'finalize' my candidate keyboard layout, I'll post it here. I've followed several recent discussions about which keys should be primary vs. shifted, and I think I've got a good layout FOR ME based on how I would use it.

For those who are interested, I'm currently working with a 4-line 20-character display and a Freescale MCF51JM128 (plenty of SPIs and has USB OTG). Just because I'm familiar with it.

With BYOC hardware, you can do yer own dang layout! And a lot more, if you've got USB, MicroSD, MP3 codec or whatever...

Sorry this is a bit long. But 'you asked'!



HP 27S. However, the door prizes I won last HHC are awesome too: the long wanted 19B and the 71B. (Thanks!)

Now if I can get a 42S for under an arm and a leg.

Edited: 1 Oct 2011, 2:11 p.m.


and serial port to the side.

Make that the top.

1) HP22S - later production without the LCD window.
2) HP70 - in excellent to mint condition.


An HP97 or HP29C, I learnt to 'program' on the HP 97 when I was about 14 (my father had one) and I was hooked from day one!

Mike T.


I really only collect the Classic series, up thru the 67 and 97; mainly because I know them well and I can repair and restore them. Of those I'm only missing the HP-70.

As an engineer I've had less interest in the financials, and the HP-70 can be rather expensive.

For modern use, an HP-42S-LE would be my most desirable calculator. I hope one day it will be produced.


A late HP 49G+, with serial number above CNA6XXXXXXX. Reportedly HP made a batch of "good" 49G+'s before switching to the 50G.

The 49G+ was my first HP calculator (mine is dead) and I prefer its looks compared to my 50G with its Darth Vader color scheme.

And a 42S.


1) HP22S - later production without the LCD window.

Randy, can you clarify. Do you mean there was a 22s with the recessed bezel? Singapore made? Didn't know that.

Do enlighten me why HP made calculators with clear cases. thanks.

i think it's funky too.


A long wish of mine - that HP would sell a custom ROM version of Casio's DataBank calculator watch as an RPN scientific calculator watch. Casio's scientific calculator watches of the 1980s, like many HP calculators, sell for many times their list price on the used market. An RPN version would be great!

Yes, today's smartphones reduce the need for this - but I'd still like to have one...


This helps to control the mechanical construction of the case.


I don't have any clear case machines but have a blue (think Smurfs) 41 case, which might be one of a kind.

Outside of HP or former HP employees, these unusual cases are rare. Clear is the most common.


Great to hear that you like my calculator pictures :-) As time allows I will add more ...


The problem with HP calculators/computers is that there is not a single Holy Grail, there are many :-)

My top favorites are: 41CL, 41CY, 9100A, 9845C, 65, 85, and from a collector's point of view a 95C.


I thought this was also for sales and demonstration purposes, so people could be impressed by the cool electronic components inside.


That is true Juergen. What I have to have at any one time can change without warning too! My holy grail non-HP right now would be an Elektronika MK90 - I haven't seen one listed on TAS for a few years now. Cheers, Keith


Make that a USB port. Jeez, guys, it's 2011!




Don't think so. Those were the days before 3D CAD.

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