Sinclair ZX81

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SinclairZX81 post Sinclair ZX81

Sinclair ZX81

The Sinclair ZX81 was the first cheap, mass-market home computer which sold 1.5 million units before being discontinued in 1984. It was truly groundbreaking and allowed the general public to get their hands on something that was previously only available to companies and hobbyists with large amounts of money.

Sinclair ZX81 datasheet

  • Date of creation: 1981
  • Developer: Sinclair Research
  • Manufacturer: Timex See
  • Discontinuation: 1984
  • Units sold: 1500000
  • Technical data
    • Weight: 350 g
    • Processor: Zilog Z80
    • Memory: 1 kB (expandable to 16kb)
    • Video: TV or TV monitor
    • Operating system: Sinclair BASIC

However, those who rushed out to buy a computer Sinclair ZX80 will probably have regretted it after the launch of the Sinclair ZX81 (Timex Sinclair 1000 and 1500 in the US). For a start, it was half the price (£49.95 or £69.95 in kit form), used only five chips (the ZX80 used 21) and had a much better BASIC programming language.

Like virtually all other home computers of the time, programs were loaded and stored on the Sinclair ZX81 via an external cassette recorder, which was the most popular and cheapest method in the early 1980s, although not always reliable. Floppy disk drives were available as extras with other, more expensive computers, such as the Atari 800the Commodore Vic 20 and the IBM PC.

sinclair-ZX81
Sinclair ZX81 16

Although the Sinclair ZX81 was by far the cheapest computer of the time, it was also the least powerful. It had only 1kB of RAM, expandable to 16kB. With a maximum resolution of just 64 x 44 characters and a monochrome display, the IBM PCThe Atari 800, with its 640 x 200 res, 16-colour screen, and the Atari 800, with a 320 x 192 res, 256-colour screen, far surpassed it, but you had to be well off to buy one of these computers at the time.

A IBM PC cost 1265 dollars, a Atari 800 899.95 and a Commodore Vic 20 260. So, at $99.95 the Sinclair ZX81 was truly affordable and allowed more people than ever to join the home computing revolution.

Timex in the United States

In the early 1980s, the world's largest computer market was in the United States. It was an essential market for a computer manufacturer. Although Sinclair sold the Sinclair ZX81 and the Spectrum through mail order in the US for a time, the biggest American success of the Sinclair machines came through the company's partnership with Timex.

The American giant was already Sinclair's main contractor for the construction of the Sinclair ZX81 y Spectrum at its plant in Dundee, Scotland. Sinclair was doing well in the US (by June 1981 it was selling between 18,000 and 20,000 ZX81s a month, more than the combined unit sales of Tandy, Apple and Commodore) but quality problems were dire, with only one in three machines actually working. An alliance with Timex was the obvious answer, and led to four officially licensed clones, produced between 1981 and 1984.

These clones were the TS1000 (clone of the Sinclair ZX81 with 2K RAM), the TS1500 (ZX81 clone with 16K RAM), the TS2048 (an upgraded ZX Spectrum 16K) and the TS2068 (an upgraded ZX Spectrum 48K).

Just before Timex Computer Corporation will launch its 2068 model in the United States, a newsletter called Ramblings (published by Timex) had an article about the 2068. TS2016the TS2048the TS2068 and the TS2072. The TS2016 was withdrawn due to the launch of the TS1500. The TS2048I had, of course, the bank-switching daughter card installed and the replacement of the VHF modulator and some other minor changes to create the TS2068. The TS2072 was the original name of the TS2068 as Timex advertised a total of 72K of memory?24K of ROM plus 48K of RAM.

In 1982, the vice president of Timex attended a meeting of the North Bay Timex Users Group in San Francisco. He brought with him questionnaires about what we would like to see in the next phase of the Timex line. He also brought a prototype of the Timex Sinclair 2000. Yes, a prototype existed. It was basically a ZX Spectrum redesigned in a silver-plated box.

It should be noted that all the boxes of the TS1500 were originally designed to be used as a box of the TS2000. The following year, the vice-president (who later became president of Psion) returned and said that he had visited Sinclair Research, LTDwhere he learned about the plans for the Sinclair QL and returned to the US in a hurry to reissue the 2000 series and make it as similar as possible to the new Sinclair QLusing the Z80A platform.

Timex Sinclair 2068 Sinclair ZX81
Photo by Gregory F. Maxwell

The engineering team of Timex was divided with its decision on which direction to support (continue with the advancement of the 2000 series or jump to the 3000 series). This is another reason why Timex had such a long delay in the release of the 2068as well as its peripherals.

The cartridge units of Timex (same as on Spectrum models only silver) and the expansion bay of the TS2065 (four prototypes were created). Sunset Point Electronics (if it still exists) had marketing photos of these computers and the photos, as well as an article were published in the magazine Time Designs.

Here are a few advertising clippings of the revolutionary computer created by Sir Clive Sinclair. Enjoy ?

  • Sinclair ZX81 advertising Sinclair ZX81
  • Sinclair ZX81 advertisement 2 Sinclair ZX81
  • Sinclair ZX81 advertising 3 Sinclair ZX81
  • sinclair ZX81 Sinclair ZX81 magazine

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2 thoughts on “Sinclair ZX81

  1. Avatar of Duroweek
    Duroweek says:

    The first computer I ever saw in my life. I played and programmed games with my neighbour, who was the owner, and me. We had a blast, that was magic with the basic programs we made. It was an unforgettable time. And from there the jump to the spectrum 48k.

    • mrbyte says:

      At the time I did not have the opportunity to get to know this computer and the truth is that it seems to me to be a very successful machine considering the characteristics at the time of its release and the price. Of course, Mr. Clive knew very well what he was doing and he hit the right key. ?

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