Vintage Calculators Web Museum - The Pocket Calculator Race

[ortek_service]

FYI - I've just received a link to this extensive webpage, that I don't recall seeing before:

http://vintagecalculators.com/html/t...ator_race.html

Quite a few pre Intel 4004 Busicom (Even if that turned-out to be too expensive to be used in much other than the Busicom) ones.
- And still today, ASIC's are used, rather than a general purpose uC with calculator program firmware, that had been an inspiration for the 4004 uP (Although now found not to be technically the first 'single-chip' uP, as there was a lesser-known device for the military)

I think I've only got the Commodore one from the 1970's - The first one we ever got / I used. Although I did later acquire a slightly-different to model shown Sinclair one, and alzso used to have a similar-looking HP programmable one to the HP-35, that had a magnetic strip reader / writer.

I imagine Tony Duell has a few others if these.....

And I never realised there had been an 'LED Shortage' in 1973, but maybe these were the cause of sudden increase in demand (Like with PC's and RAM, with new version Windows requiring much-more)

[Paul_RK]

It's a fascinating tale of rapid development and the need, at least in the case of the more innovative companies, to be economically viable while attempting to stay ahead of the game and hasten the latest advances to market. I've a cross-section of machines almost all rescued at little cost from local auctions and flea markets, starting with an Anita Mk8 and including a Casio fX-1, a very early scientific calculator

https://www.oldcalculatormuseum.com/casiofx1.html

- my example lives in a felt-lined wooden carrying case with leathern handle, and still works as intended. Must admit I'm flummoxed by the scale and nature of production that can now allow a viable 8 digit calculator to retail at £1.50 inclusive of the single AA cell required to power it!

Paul

[DrStrangelove]

I have a Commodore 4148R scientific calculator "somewhere". It has a led matrix type display rather than the common or garden 7 segment of the later 4190R I bought about 18 months later.

The 4148R was £79.95 and the polar rectangular conversion only worked from 0 to 90 deg.

The 4190R was £39.95 IIRC. The polar rectangular conversion worked in all 4 quadrants & it did hyperbolics as well, plus shedloads of stats functions I never used.

I also have a Thornton slide rule and a little 6" slide rule that had rather more use.

Back in 1972 I remember a salesman demonstrating a 4 function calculator in the Physics lab. It was expensive & mains powered.

In 1973 someone had one of the first Sinclair calculators that was 4 function & cost £80.

[ortek_service]

Those Casio FX-1's could unfortunately fall victim to those after the Nixie tubes - especially as they have quite a few digits (maybe more than some later LCD ones) - but maybe now worth keeping complete, as no doubt quite rare.

I've never used or seen a Commodore Scientific calculator - The first Scientific Calculator I saw / used & owned was the LCD Casio FX-82 that we all had to buy via the School in the early 80's. I've still got one of these, and they were so low-powered that some still have the Blue Casio AA batteries in them, which they came with.

Whereas the earlier Commodore Red LED ones rather ate the PP3 battery, and drew too-much current for it to work off some cheap '555 White Elephant' PP3's you could buy in Markets back then.
It had a external PSU jack-socket on it, but the official Commodore 9V PSU had a rather cheap transformer that buzzed loudly and my Dad wrapped loads of masking-tape around it to try and quieten it!
I ended up stripping the PSU down, and using the case to build a small LM380 Amplifier project in. But I might try and restore it back to a PSU, as I still have the case and the Calculator.

I've also recently picked up some more of the same / similar Commodore ones - Still in the box - for around £1 whenever I've seen them at radio rallies etc.

[ortek_service]

Originally Posted by Paul_RK

>>
including a Casio fX-1, a very early scientific calculator
https://www.oldcalculatormuseum.com/casiofx1.html
>>
Paul

That site also features quite a few other similar ones, on the home page: https://www.oldcalculatormuseum.com/#gsc.tab=0

Where under 'Links to other Calculator sites'
https://www.oldcalculatormuseum.com/...html#gsc.tab=0
there's lots of links to other ones.

[Radio Wrangler]

I have an HP45 which I got as a 21st present (HP staff price helped as well)
The HP35 was pretty much the first scientific pocket calculator. The 45 fixed a couple of foibles and an increase in memory density allowed an increased array of functions. Mostek chippery.

Bit big for pockets, it has a really posh leather pouch to go on your belt.

David

[Paul_RK]

Calculator use was only gradually gaining approval in my time at school, ending in 1977, and there was no recommended model never mind a compulsory one: I had a Sinclair Scientific which the years have somehow taken away, then a green display Commodore SR1800 that I still own, a little down market from Dr. Strangelove's.

I wouldn't have imagined the fX-1 would be in much danger of being cannibalised for its Nixies, at least while it's working, but I suppose stranger things have happened. I think I paid about £15 for it, somewhere in the early '90s, a little after I bid £1 for the Anita Mk8 to keep it from the auctioneers' skip.

The other two instruments below are agreed on the square root of 63, but the one on the left would have cost something like two weeks' gross average pay in the early '70s, and its companion about five minutes' average earnings today.

[Leon Crampin]

I brought out my much loved and used HP-41 the other day, wishing to use one of my ancient but highly useful - to me - programs. Alas, completely dead.

My initial fear was for the loss of several such programs, which although backed up on mag cards, would not now be readable due to the demise of the reader's rubber drive rollers. On testing, all 4 N type cells read about 1.35 V which should suffice. In fact, using my standard short circuit test with an AVO on the 100 mA range, one (Duracell) cell was open circuit. Luckily, there was no chemical leakage.

To HP's great credit, all programs were fully functional on fitting 4 new cells.

A truly great machine which still gives me pleasure to use. What a shame that this organisation which made such wonderful products (even the "hard to trigger" 'scopes) ended up as a complete basket case.

Leon.

[ortek_service]

Originally Posted by Paul_RK

Calculator use was only gradually gaining approval in my time at school, ending in 1977, and there was no recommended model never mind a compulsory one.
>>

IIRC, it was when starting Secondary school, that they wanted everyone to have the same Scientific calculator so that they could teach how to use the Trig etc. functions. The School probably got a bulk discount, and I don't think they cost that much even back then in early 80's

Originally Posted by Paul_RK

>>
I wouldn't have imagined the fX-1 would be in much danger of being cannibalised for its Nixies, at least while it's working, but I suppose stranger things have happened. I think I paid about £15 for it, somewhere in the early '90s,
>>

I imagine the Nixies would now be worth >> £1 each, so could now be in danger of that at £15 for one. But I expect the FX-1 would now be worth a lot more / there wasn't so much interest in Nixies back then (or most retro electronics, pre online auctions, when most was just sold cheap at rallies / car boots / given away or thrown-out)

Originally Posted by Paul_RK

>>
>>
The other two instruments below are agreed on the square root of 63, but the one on the left would have cost something like two weeks' gross average pay in the early '70s,

I think the earliest Electronic Calculators (Pre use of even MSI / any? IC's?), cost even more than that - Plus cost far more / were less reliable / just as large and heavy as mechanical calculating machines that were around before these. So people mostly stuck with the old mechanical ones, until Electronic ones advanced and became more-affordable.

[Paul_RK]

Originally Posted by ortek_service

I think the earliest Electronic Calculators (Pre use of even MSI / any? IC's?), cost even more than that

To be sure - the Mk8 was £355 in 1961, most of a year's wages for many, but of course few if any private individuals would have sought to buy one. It has one transistor, ten ECC81 valves, 180 or so cold-cathode tubes and a dekatron, and weighs a touch over 30 lbs..

[kalee20]

The personal calculator business was phenomenal, a brand new product, satisfying a need that existed for millennia - all within the space of half a decade.

What's astonishing is that Sinclair was up there among the big players - Texas, Commodore, HP - and stealing market share.

I still have my Casio fx-501P programmable (£54.95 in October 1983) and it's used on an almost daily basis at work! It was expensive at the time, but it's been a very good buy.

[Bazz4CQJ]

Bowmar; after Bowmar, everything else is just buffalo.

B

[Aub]

The slide rule was my calculator until I could finally afford an electronic one in 1977, bought from Jessup's in Leicester.

Aub

[TonyDuell]

Originally Posted by ortek_service

I imagine Tony Duell has a few others if these.....

Not too surprisingly I have 'taste' and like my calculators not to have a '=' key

I prefer the desktop calculators as they are easier to understand and repair. I have a couple of HP9100Bs (discrete transistors, core-on-a-rope microcode ROM, that wonderful multi-layer PCB ROM) and the TTL-based HP9810, HP9820 (OK, that one is infix notation) and HP9830 (may well be the first personal computer) along with later models.

Other desktops in my collection include one of the IME models, the Casio AL1000 and AL2000 and a Toshiba Toscal using discrete capacitors as dynamic memory. The last is in need of repair, an interestng future project.

For pocket calculators, I don't regard my HP41s, HP71s, HP48, HP49, etc as being part of the collection as I use them on the bench for calculations. I will admit that my older HPs (35, 45, 55, 65, 67, 97...) only rarely get used now. Got most of the HPIL peripherals for the 41s and 71s too.

Got a few Casio machines, nothing spectacular, and TI's (SR50, SR51A, TI58, TI59). Much prefer HP to use. I can see a Sinclair Scientific from where I am sitting but that thing is plain horrible. I'd rather use a handheld analogue calculator -- aka a slide rule -- which is probably more accurate.

Can't justify a pocket mechanical calculator (Curta), but I've got a few desktop machines. I found a Busicom one some years ago, the name is interesting as I'd not heard of the company other than n connection with the 4004. I do have the courage to strip and rebuild those too, they're actually quite simple when you understand them.

[ortek_service]

At a Radio Rally on Monday, I picked up a large-box of Practical Electronics magazines, to try and complete few missing issues / the Free Blueprints these (usually rarer to find still in these) I had in my collection. And whilst going through these, I discovered the:
PE Digi-Cal 'High Speed' 8 digit LED display Calculator Project (In 11! parts from July 1972 to May 1973)
- As usual, you can now find most PE issues on archive sites, with link to the first one, here: https://worldradiohistory.com/UK/Pra...cs-1972-07.pdf

This design is all implemented in 74 logic IC's, uses a whopping 144 of these! So more of a small desktop computer size
- And they didn't use the recently-launched Intel 4004 etc, originally intended for this application.
All of these are mounted across 12off 'Shirehall Dualine DL109/xx (+ optional DL107/44) Plug-in 'Logic' matrix-board cards, that just have tracks for edge connector and DIL footprints with pads joined to these. So you had to use point-to-point insulated wire links to connect these up! (Only photos of these were shown, so once IC's were positioned, you had to follow the circuit diagrams to work out all the required connections). With these plugging into a hand-wired (also point-to-point wired? as connectors were double-side?) backplane matrix board.

They estimated the cost was £110! (Inc. 7.5%? VAT?) to do a bulk purchase for most of the parts (Exc. Power Supply & case)

I wonder how many people ever attempted to build this very-ambitious project, given the long time-scale and cost (maybe like those notorious things you could build by buying in weekly-parts, for around a year in - with first-issue often much cheaper to draw you in - so total cost was rather high).

And how many ever managed to get it to work!
Testing (especially debugging !) this must have been a nightmare, and seems you started-off with a very low speed main clock to aid this, then increased it to as high as it would work to - estimated to be > 1MHz, as achieved in prototype. Although you could also make an 'extender-card' to work on the cards.

This must have been one of their most-ambitious projects (even compared to Electric Piano ones in some of those issues)
With the design probably rather-quickly obsoleted only a month after the start issue, when in Sep 1972 the Sinclair pocket calculator was launched at 'only' £80 (+VAT): https://en.wikipedia.org/wiki/Sinclair_Executive

[TonyDuell]

I remember the Digical project and have all the original magazines here. When I seriously looked at it about 10 years later I thought that it wasn't a good design. It doesn't handle negative numbers for a start. And doesn't it do multiplication by repeated addition (rather than shift-and-add)?

There aren't that many more ICs in an HP9810, and that is a full programmabl calculator that can be interfaced and extended. The only 'complex' ICs in that machine are ROMs and RAMs, the processor is built from TTL.

My limited experience of looking at desktop calculators suggests that the earlier designs were sort-of based on the mechanical calculators of the Brunsviga type. Dedicated input, accumulator and counter registers and logic to link them. Then the better designers realised it was as easy to make a general purpose processor and run firmware on it to make it a calculator (look at the 3 very different (to the user) HP9810, HP9820, HP9830 machines. A lot of the internalss are the same).

On a mechancal calculator copying a number from one register to another is non-trivial(the 'back transfer' from the accumulator to the input register on such machines works by clearing the input register, coupling (gears) the accumulator wheels to the input cam plates and then clearing the accumultor. As the wheels go to zero the transfer gears move the input cam plates). On an electronic machine it is much easier.

Finally, I think you'd learn a lot more building a calculator from TTL rather than soldering in an LSI calculator IC. Especially if you have to find faults in it! I know I'd much rather attempt to build a machine from TTL than use an LSI device such as a microcotroller (now).

[Vintage_RC]

I've still got the Faber Castell slide rule that saw me through 6th form and university. Like many on this forum I lived through the rapid development of the electronic calculator. My first scientific one, sometime in the 70's, was made by a division of Analog Devices, it didn't have an exponent function so rather like a slide rule you had to carefully manage the magnitude of the numbers. I seem to remember it cost £50.

[60136 Alcazar]

Originally Posted by Paul_RK

I had a Sinclair Scientific which the years have somehow taken away.

There is an auction coming up soon with a Sinclair President Scientific calculator - lot 236 in the Auctioneum at Bath & East Bristol Auctions on 12/9/23.

[Phil__G]

Originally Posted by 60136 Alcazar

There is an auction coming up soon with a Sinclair President Scientific calculator - lot 236 in the Auctioneum at Bath & East Bristol Auctions on 12/9/23.

How do you get to know about these things please, I miss loads of events cos I dont know they're happening!
Recently missed the Opensource Hardware camp, in Hebden Bridge, not far from me, had no idea it was on

[ScottishColin]

I potter on this site sometimes - the President is listed here when I search for Sinclair.

https://www.easyliveauction.com/cata...searchOption=3

Colin.

Originally Posted by Phil__G

How do you get to know about these things please, I miss loads of events cos I dont know they're happening!
Recently missed the Opensource Hardware camp, in Hebden Bridge, not far from me, had no idea it was on