back to article El Reg's contraptions confessional no.5: The Sinclair Sovereign

Time was when having a calculator felt about as hi-tech as owning smartphone does these days. Lester Haines relives the experience when these small objects of desire weren't just about doing the numbers, but were even touted as status symbols. Sinclair Sovereign Having risked the lives of the specialist team members tasked …


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  1. Anonymous Coward
    Anonymous Coward

    Sinclair calculator, pinhole camera?

    "Although the 30-something calculator worked for a couple of minutes, the LEDs quickly faded before I could hit the shutter button."

    Im guessing your photographic equipment comes from a somewhat earlier vintage...

    1. Scorchio!!

      Re: Sinclair calculator, pinhole camera?

      My DSLR has a shutter button, as Wikipedia confirm ( ):

      "Focusing can be manual or automatic, activated by pressing half-way on the shutter release or a dedicated AF button."

  2. MrT

    I remember the Executive...

    ... because oddly one guy I worked with still had one on his desk a decade later, but this one passed me by. It was the stories that others used to relate about the howling errors he used to make simply because the calculator gave a number, and this very experienced engineer forgot the basic "estimate before you calculate" rule. I guess he kept it like some sort of hunting trophy...

    This design looks different but it limits the display size for further development. It does look like it could be operated whilst held in one hand, which was something that others of that era couldn't manage - but then they tended to stay on the desk or drawing board even though they were pocketable.

    Odd, at a time this sleek design for a device that probably stayed on a desk came out, we had the first slab-like TV remotes that took two hands to hold (like the Grundig I had for a long while)

    1. Stevie

      Re: I remember the Executive...

      Heh. Calculator Love - Unrequited.

      I was in a bank about 6 years ago and deposited checks (this was in the US so US spelling) for something like $3.50, $11.80 and $4.20. The embryo behind the counter punched at his calculator and announced my total of $19.50 was wrong. I begged to differ so he rolled his eyes and showed me his calculator with $15.50 showing.

      It can't be that I said. He argued. I pointed out that the dollar amounts alone could be easily seen to add up to more than $15, and the cents came to more than a dollar on their own. He then grabbed a piece of paper and did the sums, reluctantly agreeing that the amounts was indeed as I had stated.

      I left him beginning to realize that everything he'd used that calculator for that day was now suspect and his drawer reconciliation might be a thing of ugliness that evening.

      1. Captain Scarlet Silver badge

        Re: I remember the Executive...

        Hmm sounds like a line from the display no longer showed on the LCD so 9 became 5, 8 became 6.

  3. saundby

    Got the Cambridge, but not this.

    I never saw one of these, but with a Cambridge Programmable in hand I wouldn't have been tempted. It's still in my desk drawer, stored in a case that outlived the TI-30 it came with. I sacrifice a pair of batteries to it each year for old time's sake.

    1. Stevie

      Re: Got the Cambridge, but not this.

      "Pair" of batteries? Doesn't the Cambridge take four AAAs? TTL Logic power requirements, no?

      1. MrT

        I had one of that vintage...

        ... also red LEDs for the display, which took 6xAAA cells. Soon replaced those with a single PP3 (6xAAAAs internally) wired across first and last contact and stuck on the outside of the case with insulation tape.

        It was a good job that it did the power distribution properly inside, instead of taking a line out of the battery at 4.5V to run the logic - the last time I noticed something like that was on an old robot arm for my BBC Master, and only because I was trying to sort out a 9V PSU feed instead of sacrificing another stack to the god of C-cells...

        1. Stevie

          Re: I had one of that vintage...

          "... also red LEDs for the display, which took 6xAAA cells"

          Eh? My Sinclair Scientific had red LEDs (the only sort you could get at one time) and it ran/displayed find on four AAAs. Still does.

      2. saundby

        Re: Got the Cambridge, but not this.

        I give it one 9V battery about every six months. It's the pregnant programmable Cambridge.

        1. MrT

          Oops - I wasn't very clear...

          ... I didn't own the Sinclair calculators, but another more wedge-like 70's calc, a HP model which had an LED display, all clicky ORIC-style buttons and a display that flickered with each press.


  4. chivo243 Silver badge

    8 Years until 1984

    In 1984, I was given a solar powered Radio Shack calculator with the same functions It’s about the size of a credit card and about as thick as 3 or 4 credit cards, and believe it or not, it still works. Haven’t had to replace the batteries yet!

  5. P0l0nium

    Shiny..rectangular..rounded ..

    Sinclair should have patented the concept..

    "A shiny, rectangular ,technological THING with rounded edges, restricted functionality and a short lifetime. Acts as an extension to your self-esteem and may be attractive to other shallow-minded fools.

    Can be used to waste large amounts of personal time."

    He'd have made a fortune.

    1. Anonymous Coward
      Anonymous Coward

      Re: Shiny..rectangular..rounded ..


  6. We're all in it together

    The Golden era

    Looks like a remote control that can add. I wonder what Sir Clive is up to these days?

    1. Simon Harris

      Re: The Golden era

      Since my TV can receive Channel4+1, E4+1, etc. a remote that can add may be an important feature.

      1. Anonymous Coward
        Anonymous Coward

        Arithmetic TV channels

        @Simon Harris; That's nothing... there was briefly a "BBC News *Minus* 1" timeshift channel, but it was cancelled after several incidents where it transmitted breaking news events before they happened. OFCOM forced them to shut it down as they reckoned it violated the law. The law of cause and effect, that is.

        I also heard a rumour about a "Channel i" once, but it turned out that this was purely imaginary. Ironically, the timeshift version, "Channel i + 1" wasn't entirely imaginary; there were some bits that were real, but to be honest, the situation was quite complex.

        1. A J Stiles

          Re: Arithmetic TV channels

          I'd have upvoted you there, if you'd only called the square root of minus one by its proper name of "j".

    2. jonathanb Silver badge

      Re: The Golden era

      He is still trying to break into the electric bicycle market -

    3. Dodgy Geezer Silver badge

      Re: The Golden era

      I can tell you what his son's doing...

      1. Dom 3

        Re: The Golden era

        Iain's Clive's brother, not his son.

  7. YeahRight

    I've still got one of these in my 'doesn't work, was fairly crap when it did but can't bear to dispose of' box under the bed. There's a Sinclair Black Watch ion there too. Oh and ZX81 (not crap though and still works)

  8. Randolf McKinley
    Thumb Up

    Ahh, the days of real calcluators

    I still have and use most working days my HP41CV calculator I bought new when they first came out in 1981 or '82 in the last year or two of my engineering degree. Reverse Polish like all good calculators should be. I still have the magnetic card reader and the printer that went with it although I've not used them for a long long time, and a bunch of the plug-in ROM packs with pre-written programs for advanced maths and circuit analysis and stuff. Of course they don't get used any more because anything more complex than a bit of a sum gets done in a spreadsheet or a real program, but in those days it was the peak of engineering programming, and you still can't beat a good calculator for doing simple maths.

    Sadly got a HP41 simulator for my jesusphone too. It's pretty good, but the phone display is a bit to small to do the original justice.

    1. Anthony Hegedus Silver badge

      Re: Ahh, the days of real calcluators

      I bought a 41CX in 99, "new in box", and it's bloody marvellous. I had a plain old 41C back in 1980, which sadly died, so buying a "new" one all those years later really brought back memories. It's amazing how you can get attached to a calculator...

    2. whuffie

      Re: Ahh, the days of real calcluators

      I still have my 41CV. It was bloody expensive (around AUD$400 as I recall).

      The two major advantages of Reverse Polish Notation on a calculator:

      1. faster keying

      2. absence of the "=" key meant fewer wanting to borrow it!

      1. Kubla Cant

        Re: Ahh, the days of real calcluators

        The first electronic calculator I used was in a council Treasurer's office. It was about the size of a cash register, and had eleven rows of eleven keys (0-9 and decimal), and the display used Nixie cold-cathode tubes. This was about five years before decimalisation, so we had to convert £sd to decimal before entering and back again to use the result. A conversion table was stored by the calculator, but I'm still surprised it was worth the effort.

        In the early 70s I had a job where I spent weeks performing calculations on magazine readership statistics using a slide-rule. I tried to persuade my boss to buy an electronic calculator, but it appeared that my time was cheaper than the calculator, so all I got was the occasional loan of horrible old electro-mechanical things, still with 11x11 keyboards. The basic models would only add and subtract. The more advanced ones could multiply and divide, but the interminable gear-grinding process made you wish you hadn't bothered.

        1. Stevie

          Re: Big Calculators with Nixie Displays

          Do you remember those gag calculations where you punched in the values then hung upside down from the ceiling light fixtures so you could read "SHELL OIL" or "BOOBIES" in the soft glow of the nixies?

      2. Anonymous Coward
        Anonymous Coward

        Re: Ahh, the days of real calcluators

        Back in graduate school one of my good friends had an HP RPN calculator he used while teaching. His students . One April 1st, he sent a letter to HP informing them he was planning on filing suit in the sum of $0.01 because he could not loan his calculator to his students because it used RPN. A few months later he was summoned to the University's legal office asking about this lawsuit. He explained that it was all a joke (note the date) and was then instructed to write a polite letter explaining this to HP. We thought this was the end of it, but a few months later my friend received a complimentary calculator in the mail from HP that used infix notation. At least someone appreciated his joke!

  9. bitten

    Came after the HP-25, so?

    1. harmjschoonhoven

      Re: Came after the HP-25, so?

      I bought my HP-25 in august 1975, the year it was launched (pun not intended).

      The HP-25 was the first affordable programable calculator with floating point and scientific display, trigoniometric functions in degrees, radians and grads, statistical functions and much more.

      Never returned the Service Card. Still going strong with new Ni-Cd cells.

      1. Martin Gregorie

        Re: Came after the HP-25, so?

        I bought my HP-25 in august 1975, the year it was launched.

        I bought mine a year later, 1976. It was my sole calculator until I got an HP-28S in 1990, at which point the HP-25 was retired, though I still have it and it, and its charger, still work if I clean out the dead NiCds from its battery holder and replace them with a pair of new NiCd or NiMH cells.

        The 28C is more useful for programming, since it understands hex and logic operators. Its also the first bit of kit I got where the manuals outweigh the device and occupy several times its volume. I use it whenever a spreadsheet would be overkill.

  10. YeahRight

    Actually surprised that Nokia never ripped off this design for a phone. It would have been highly desirable in 2003

    1. Robert E A Harvey

      They did. I saw one in Brazil at about that time, along with one shaped like a pen that was /entirely/ voice-op

  11. Anonymous Coward
    Anonymous Coward

    Divide by zero

    I had a Sinclair Cambridge. It went through batteries too quickly and there was no error handling for divide by zero which resulted in all the digits in the display counting rapidly until you powered it down!

  12. photobod

    Says it all really...

    ...about the habitual mis-use of the term 'design'.

    "The Sovereign secured a 1977 Design Council Award for John Pemberton, the man responsible for its sleek lines, although technologically it was on a hike to nowhere."

    So, when it got a 'design' award, form the Design Council, it was actually for styling and nothing at all to do with what 'design' is supposed to be about, the ability to actually work properly. This is the mis-use which has led us all the way to US 'design' patents for rounded rectangles.

    1. Stuart Castle Silver badge

      Re: Says it all really...

      The thing is, there seem increasingly to be two facets of design in use. The practical facet which is how a product works and the visual facet which is how a product looks. I think that this is partly because people who tend to be good at designing the functional part of a product are not always that visually orientated and those that are don't always understand the technicalities of a product..

      For instance, a couple of years ago, we needed a new system for booking out equipment to users. We had no budget to buy in a system, or employ someone and only a few staff with the time and skill required to design one. So, we got together what staff we had. One colleague designed the backend database stuff and web services required (we had several systems all needing to access the same data, so it was easier to use web services to manage access to that data, one designed the look and feel of the websites involved and I designed the code used to connect the two..

      Now, my friend who designed the look and feel of the site is very visually oriented. So much so is now a video effects tech for the movies. But he has a very limited ability to understand coding. I have a good knowledge of coding (in multiple languages, both web and non web based) and while I am quite capable of producing a fully usable site, it would not win any awards for it's appearance..

      The Design council have always seemed to be concerned with how a product looks rather than how it functions.

      1. Naughtyhorse

        Re: Says it all really...

        Excellent post however one small correction......

        'The Design council have\ only ever been \concerned with how a product looks rather than how it functions.'

        apart from that hit the nail right on the wossname

    2. Terry 6 Silver badge

      Re: Says it all really...

      It's also the road that leads to countless other devices that look good, but don't actually work very well in the real world.

      Legions of coffee grinders that ornament the kitchen, but can't grind beans, dishwashers that look lovely with plates stacked neatly inside them, but haven't got space for a soup bowl, fridges with delightful storage slots for holding bottles that are all about 2cm too low for a plastic milk bottle to fit. And my favourite, the lovely new dinner plates that are just a fraction of a cm too wide to go into a standard single-cabinet sized cupboard.

    3. Alan Brown Silver badge

      Re: Says it all really...

      The "design council" has always been about style, not function.

    4. John Brown (no body) Silver badge

      Re: Says it all really...

      "So, when it got a 'design' award, form the Design Council, it was actually for styling and nothing at all to do with what 'design' is supposed to be about, the ability to actually work properly."

      Yes. You're probably looking for the Engineering Council.

      1. Anonymous Coward
        Anonymous Coward

        'Design' Vs 'Industrial Design'

        I studied 'Product Design for Manufacture' instead of the visually-focused, traditional 'Industrial Design' which has its origins in just sticking a fancy case over what the engineers have already created. My course, as its name suggests, was created to bridge the gap between the Industrial Designers and the Manufacturing Engineers who actually have to work out how to make the product at an economic cost.

        When I started the course, the most famous Industrial Designer was probably Phillipe Starck or James Dyson, and most of us students didn't have a mobile phone or a computer. Starck's tripod lemon squeezer was a design icon, though our lecturers assured us it didn't actually work very well. Over the next few years, we saw a blue translucent Mac with no floppy drive, Windows 2000 would delete my ZIP disks, some iPod thing cost £600, cameras took floppy disks, Palm licensed their OS to Handspring and Sony, Macbook Titanium and G4 Cube were released, and there was lots of talk of 'digital convergence' (this crazy idea that your phone, music player, PDA and camera would become the same device).

        To my mind, 'Design' is a process, and Industrial Design or Graphic Design is merely that process applied to a more narrowly defined area. It is telling that Braun's Dieter Rams describes himself as a 'Form Engineer', and not a designer, because of the way that the word 'design' has been misused. Rams was concerned with how an object worked, how it was used, and how it was made, in addition to how it looked.

        This division was also built into the CAD tools that were available... there was free-form sculptural CAD like 3D Studio Max, and then there were the Parametric CAD packages like ProE or Solidworks (actually, at the end f the nineties Parametric CAD was only beginning to come down from the mainframes to workstations) that engineers used which allowed dimensions to be defined relative to each other. Both approaches have their advantages in certain cases, and the new 'Big Thing' in CAD in the last few years has been the emergence of packages that allow both approaches to be used in the same environment.

  13. banjomike
    Thumb Up

    Casio FX-502P Programmable

    In 1977 I bought a Casio FX-502P. I still use it daily and it is on its fifth set of batteries in 36 years. Georgeous calculator, programmable (not in BASIC), with printer and external storage!!. Extremely usable and fast unlike some of the Sinclair models where you could actually watch the display changing while it calculating the answer.

    1. Simon Harris

      Re: Casio FX-502P Programmable

      I only had the FX501 - I think the same as the 502 but with only half the program memory. The calculator is long gone, but I still have the cassette interface somewhere.

      It came with an excellent manual full of useful programmes.

      The cassette interface could either store programmes using the 300 baud CUTS standard or render them as tunes - Für Elise springs to mind as one of the examples from the manual.

    2. JohnG

      Re: Casio FX-502P Programmable

      I had a Casio fx-201P - this too was programmable but had a nice green vacuum fluorescent display (which meant that I almost always used it on mains power). I still have it and the associated programming manual. It still works.

  14. Tom 35

    TI SR-51-II

    I bought one when they first came out, lasted me through high school and university.

    I did something I have not seen since. It calculated to 13 digits and displayed 10. So if you try...

    10 / 3 = * 3 = you got 10 not 9.9999999999

    1. Anonymous IV

      Re: TI SR-51-II

      Surely the real test is 1 / 7 * 7 = 1.00000... and not 0.999...997, or similar?

  15. codeusirae

    Calculator battery hungry supply ..

    "The calculator boasted a battery-hungry 8-digit LED display .. Two 1.35V mercury button cells provided the juice - a pretty lamentable supply if I recall correctly"

    I recall reading somewhere, where in order to conserve supply, they switched the battery on-and-off rapidly, the CMOS circuity managed to remember its previous state, this tended to make some of them self destruct ...

  16. Levente Szileszky

    IF it's Sinclair...

    ...THEN it's ZX Spectrum, the greatest PC at the time, my first machine, the one that's mostly responsible I ended up like this (not complaining at all, just stating) ELSE it's rather limited predecessor, ZX81, perhaps.

    1. Dan 55 Silver badge

      Re: IF it's Sinclair...

      Only ZX Basic didn't have the ELSE keyword.

      GO TO manual

      1. Levente Szileszky

        Re: IF it's Sinclair...

        Ouch - talk about having OCD... FYI it was a BASIC play with words, not Sinclair-specific (I didn't include ELSE in it first, for this specific reason, I just went back and edited later, to make it more obvious for non-Spectrum folks.)

  17. MacroRodent

    LED not so bad choice

    As I remember it, in the 1970's LCD:s were still pitifully illegible. You had to look at them from just the correct angle to see anything, and even then it was murky. So putting LED:s or plasma displays(*) was quite reasonable at that time. (*)= not sure if this is the correct term for the kind of flat glass vacuum-tube-like element with the glowing number segments in it. Around 1980 I used to have a Casio scientific calculator with this kind of display.

    1. Simon Harris

      Re: LED not so bad choice

      Vacuum fluorescent display is the technology you are thinking of. Very nice to look at compared to the leds behind little bubble magnifiers on TI calculators, but they did need a dc-dc converter to get the 40 or round abouts volts needed to drive them.

    2. Fair Dinkum

      Re: LED not so bad choice

      Vacuum flourescent display. I believe they still make them.

    3. Amorous Cowherder

      Re: LED not so bad choice

      Vacuum fluorescents!

      I remember my old man had a TI calculator with a vacuum fluorescent display in it, it used to sit behind a thin red plastic filter so it could try to like looked like a red LED calc. He used it for about 15 years from around '79.

      Anyone remember the Grandstand games company from the mid 1980's? They used to make lots of handheld electronic arcade game conversions using those vf displays.

  18. LateNightLarry


    Don't know if this really falls in the same category, but I had the dubious pleasure of working with a bunch of Canon TX-10 Programmable Calculators... These beasts were large, contained two cartridges, one for the program, and one for the data. The window clerks had the same machines with a different program cartridge, for daily activity on the USPS retail window; mine was the consolidation program which transferred the data from the window clerk data cartridges and consolidated it to an office total for the business day. They were prone to crashing, so I had to have at least three program cartridges for each machine, and a half dozen data cartridges for each machine. I could reset the data cartridges, but the program cartridges had to be "repaired" (reprogrammed) by Canon, and had to be mailed to San Diego by Express Mail and returned by EXM as well... Major headaches, but when we got them, they were state of the art for USPS... Now USPS is using computers that are 15 years out of date, 386, running Windows NT4.0.... and apparently no plans to replace them... Can't get the Postal Inspection Service to approve new hardware and programs. I helped set up those black boxes when we installed them in the office, and had to keep them running until I retired... Just about any problems except swapping printers, I could only call the help desk because they were locked down like Fort Knox... Just waiting for the day those old 386 boxes start crashing and they can't get parts for them.

  19. Hans 1

    What is all this royalty shit

    Why, of why do you have so many royalty-related brand names in the UK ... Sovereign or Monarch cigarettes, airlines etc etc ... I do not know what our Usian friends think of it, I guess for once we could agree on "antique crap" ...

    As for LateNightLarry: NT4 and "locked down like Fort Knox" simply makes no sense whatsoever, to me at least.

    1. Arnold Lieberman

      NT4 security

      C2 rated, don'tyaknow...

    2. Arnold Lieberman

      Oh and Royal connections

      Monarch Airlines ultimate parent company:


      Doesn't sound very British to me.

      To coin a phrase: Other monarchies are available.

  20. Tachikoma

    Two 1.35V mercury button cells provided the juice

    I'm hoping you didn't just shove a pair of 1.5V batteries in there as that may be what caused it to die after a few minutes. I collect old cameras and one thing you learn early on and sometimes at great cost is not to shove 1.5V batteries into a 1.35V device. You can buy "Wein Cells" which are a 1.35V Zinc/Air battery designed to replace the old mercury batteries.

    1. The First Dave

      Either way, I can't believe you just gave up after a single attempt.

    2. Stevie

      Wein Cells

      Are these available from Wein Sellers?

  21. Stevie


    "LCD ascendant?" In 1973?

    In my universe, though you certainly could see LCDs on expensive watches they could hardly be said to be "ascendant" until they became cheap enough to pack into watches everyone could afford - call it 1977 or thereabouts.

    LCDs were only being put into (barely) affordable calculators in the (very) late 70s and early 80s as I remember things. Cheap-as-chips calculators were still using LEDs even then. I have a programmable Commodore bought in 1979/1980 (poor memory at work) that has them, and it was a new model then.

    The main problem with Sinclair calculators that I had were the godsaweful dimple foil buttons coupled with no debouncing circuitry whatsoever.

    This was a feature of my 1974-era Sinclair Scientific (which also featured Reverse Polish operation (only) and no clear last entry to enhance the moment when a long calculation would be rendered moot by ddddddddddoubled ddddddddigits. All this and two less digits of precision than required by my university professors, at a cost only the affluent student could afford anyway (mine was a gift) unless you bought it in kit form. The Sinclair Scientific was perhaps the only pocket calculator that required the use of a pad of paper and a pen to use for any real manly calculations. On the other hand, no-one asked to borrow it more than once.

  22. Mage

    On Portable Devices: LED VFD then LCD

    Though VFD type devices date from early 1950s and LEDs early 1960s. The VFD is about 1/10th of voltage of Neon/Plasma displays and much easier to drive / matrix. Can work as low as 15V.

    VFD still used in Cars, Setboxes/Disc players, Ovens (Microwave or Resistive).

    VFD (Matrixed Triodes) and Magnetrons (Diode) are really the only two valve devices left in Volume Production now that CRTs gone.

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