Caution, explicit photos...the collection to date! The vintage people will like this!

Hello to all you vintage collectors, don't mind me, I have had the HP bug since my 25c in 1975.

My first exposure to the 67/97 dual was as a research assistant while as an undergrad. Boy talk about state of the art at that time. Well had to wait a few years but now I have 3 67's with working and restored card readers as well as the NOS 67 pictured here. The 97 also came along as you can see.

Later while doing my MSc I aquired an HP 41C which needs a new display but is not pictured here. It was so versatile that when I got my first flying job I picked up 41CX that just hit the market. Since then I have added a second HP 41CX and a bunch of accessories; the plotter, IL printer, IR printer and IR module, PPC ROM, 2 X Memory modules, Stat module and a 9114b disc drive.

So thats the history and here are some self explanatory shots I took with the new camera and a photo program.

All these calcs were restored where mentioned by me at home. I am not an electronics expert or an engineering grad but I have always enjoyed soldering and fixing electronics.

Hope you enjoy the photos.

HP 35 WITH PRINTED KEYBOARD, un-restored and in non-working condition. Lights up but keyboard unresponsive and lots of corrosion on the battery prongs. Initially bought for parts but will be restored instead.

HP 35 was in similar condition to the above when it arrived but now works and looks great!

HP 45 unrestored but in fully functional condition. The timer loses about 7 seconds a minute as usual for these prototype timers.

HP 45Q (Q for quartz!. Fully restored from a non-functioning condition. I had secured a spare HP 55 keyboard with a 780 kHz quartz crystal which I then, following instructions at this site, wired into the timing circuit. The calculator is fully functional, looks like new stock and has the accuracy of the HP 55 and my HP 41CX.

HP 55 fully restored also from a non functioning condition. The calc was completely dis-assembled, keys washed separately and the top half-spine-bottom half were cleaned. The top half had a bad white bloom in the finish and made the functions illegible. This was remedied by a thorough wash (gently) followed by drying and a matte spray varnish for plastic. I think it came out quite well and the timer is extremely accurate. After two hours the HP 55, HP 41CX and the HP 45Q were reading the same time to the second

A new old stock HP 67. I was informed by my local battery/electronics shop where they know me that a local elderly gentleman had a non functioning HP 67. Would I be interested in it. I dropped by the owners house and to my surprise was greeted by a 97 year old professor of Archeology. He was finishing a paper for publication in a journal of Archeology and required a Statistics calculator. He purchased the HP 67 new and never used it back in 1981. It sat in its' original box not unpacked for the last 30 years.

He did not want to be bothered with learning it or using the card reader etc and had purchased a Casio instead. Well I offered to sell it for him but he couldn't be bothered. I suggested that it would sell for quite a bit but he just wanted it to go somewhere where it would be appreciated.

I ended up purchasing it for $50.00 US and with that got the outer box, unused calculator, adapter, separate battery charger and original batteries still shrink wrapped. As well as a shrink wrapped HP 67 Manual, guide, quick reference card, programming pad, reciept and etc. all still shrink wrapped!

You can see the untouched label in this picture.

This HP 91 in came pieces, in a box... well the picture says it all.

Non functioning card reader and printer. Using Katie Wasserman's article on printer repair I secured an aluminum gear, which, following instructions was used to replace the gummy printer gear. I also repaired the gummy wheel problem on the card reader.

This and one of my other 67's bears the weight of my work in the cockpit. I have programmed this 41CX with some custom programs which are accessed as seen on the overlay.

You can see here the modules I use for day to day operations.

HP 01 group shot including the almost NOS stainless version

Close up of the above.

Edited: 4 Feb 2008, 9:57 p.m. after one or more responses were posted



you kill me


Wow! This is pure torture!!!

Congratulation for your collection, and I have even got a tip for my 35.




Wow! HP-41 IR module? what does it do?


Hi Geoff.

here are some self explanatory shots I took with the new camera and a photo program

Seems like I can't see any picture...

Is it just an issue o' mine or some trouble occurred?

Thanks in advance.

Best regards.


It's for wireless communication with the printer 82240. You'll find the manuals on the Museum DVD.


Buon giorno, Giancarlo!

Works fine here. Guess the trouble is on your side ;)

Edited: 5 Feb 2008, 8:04 a.m.


Guten tag, Walter.

You're right - seems like it's due to our company's firewall settings that "block" business unrelated web addresses (Websense, or something...).


Danke und auf wiedersehen.




95% of the keys on an HP-35 that didn't work...

That comes to 33.25 keys (on my Windoze calc)!

Did one of the keys only work 25% of the time?



dona nobis pacem


34/35 X 100% = 97.14%

Should have done the math before the posting ;-)


I just can say WOW !!


to complete the collection.

Cheers, Geoff


Could you tell us exactly what "matte spray" you used on the keyboards? Thanks...


What about an HP-70?


Hello Geoff,

Absolutely marvelous! and thank for making us "jealous" withe thee beauties.

I tried to get the testor silver paint marker, but no success in Europe. I tried to order one from a US shop, but they told they did now want to ship outside the States.

Is there anyone who has a link to a shop in Europe for me? or could help me in this ?


The Netherlands.


Both these products can be aquired at a local hobby store that stocks plastic models, model airplanes, railroad equipment etc in Canada and the US.

Your right, I need to find an HP 65, HP70 and an HP 80 to complete the "classics" collection then build wall rack for them.

Cheers, Geoff

Edited: 7 Feb 2008, 2:30 p.m.


I'd skip that model. IMHO it's ugly :(


I need to find an HP 65, HP70 and an HP 80 to complete the "classics" collection then build wall rack for them.

I have a spare HP-80 with an AC adapter but without a battery pack. What do you have to trade?


I've also used the Testors pen on a 35 restore. In my opinion, though these pictures look great (!), the pen results don't look that good in person. It may have just been my lack of artistic ability.


That's some of the best calculator pr0n I've seen! :-)

The restoration work is great. Very nice job on the photography, too.


I have an HP 45; the fully functional, non quartz HP 45 in the 3rd photo from the top. The battery cover has hatches on both sides but they are loose. No corrosion on the battery tabs or the wall wart (AC adapter) connectors either.

I am waiting for some after market tabs to arrive but will have to wait for that.

Cheers, Geoff




Geoff --

Sorry for the tardy post, but I'd also like to offer my congratulations and acknowledgement for a job well done -- a nice collection with restoration work, and fine photography. Thanks!

-- KS


Geoff, you make me ashamed ..

I collected several machines a few years ago and spent quite a while fixing and cleaning hp35s in particular. But they're just sitting in a cupboard now, and some of the battery packs are starting to leak again (though I have kept them separate from the calculators).

I've certainly got more of some models than I want (35, 71), and there are some rather desirable ones that maybe someone else would enjoy more than me (70, 10, albeit not perfect; 32sII NIB).

How do you other folk maintain your collections ? Do you change all the nicads every few years ? Do you rationalize them to just one of each model ? Do you carefully file them away in the hope that they'll pay your pension one day or do you use them all regularly ?

In case you think I'm just hoarding them - I do still use HP calcs every day; usually a 32sII, a 15c or a 16c. I wouldn't use anything else, and I won't part with my spare Voyagers. But the LED ones aren't likely to be used much.


I have a comparatively small collection: 33E, 41CV with Advantage, Math/Stat and Machine Des Pacs, 15C, 32sii, 33s, 35s, 48G and 49G+. I actually manage to use them all too... although lately I have been using the 35s mostly. I am a mechanical engineer and I also do a fair amount of statistics (LeanSigma) and TVM stuff.

I am studying for a PMP (Project Management Professional) exam in a couple of months and they do not allow programmables on the test - there are about thirty odd formulae to memorize - pretty basic stuff for the most part. I am looking for a non-programmable (HP RPN only) calculator at a reasonable cost and would like to make you an offer for one of your spare LED models. Please PM me at if that is convenient. Replace _at_ with you know what.

Kind regards,

Jeff Kearns


Adrian, most users have abandoned NiCad cells for direct replacement with Nimh cells. Some of these are stated to retain charge for 6 months to 85%. I just ordered 12 for longer term use here in the house where we would otherwise use primary cells. I used some with welded tabs to make a pack for the remote telephone, they last a month without attention, and don't have a memory of usage like NiCad.


It's not so much the capacity / usage of NiCds that concerns me, it's the shelf life. I have a handful of battery packs of various types, some that I've just cleaned up and others that I've repaired.

But there's corrosion again on the cleaned ones, and I've got cells lying around that I bought new that have leaked too. There doesn't seem much point getting all my packs in first class condition if they're then going to sit there until they leak again !

I'd certainly be happy to use NiMH instead (I use those in anything that has individual replacement cells already) but how do they behave long-term ? Do they leak like nicads or just go dead ?


Some Nimh cells last longer, my charger reads null if I put a dead cell in. There is a new generation of Nimh cells with lower self discharge, now widely available. I think they may be safely substituted for NiCad and charged in the calculator. NiCads leak and require safe disposal, I have never had a Nimh cell leak out of sample of 50 both AA and AAA size. I am upgrading to the newer low discharge cells to use instead of primary cells. Sam

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