Sinclair ZX81: The $149.95 personal computer (May, 1982)

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The $149.95 personal computer.

Introducing the Sinclair ZX81 If you’re ever going to buy a personal computer, now is the time to do it.

The new Sinclair ZX81 is the most powerful, yet easy-to-use computer ever offered for anywhere near-the price: only $149.95* completely assembled.

Don’t let the price fool you. The ZX81 has just about everything you could ask for in a personal computer.

A breakthrough in personal computers The ZX81 is a major advance over the original Sinclair ZX80—the world’s largest selling personal computer and the first for under $200.

In fact, the ZX81’s new 8K Extended BASIC offers features found only on computers costing two or three times as much.

Just look at what you get:
* Continuous display, including moving graphics.

* Multi-dimensional string and numerical arrays.

* Mathematical and scientific functions accurate to 8 decimal places.

* Unique one-touch entry of key words like PRINT, RUN and LIST.

* Automatic syntax error detection and easy editing.

* Randomize function useful for both games and serious applications.

* Built-in interface for ZX Printer.

* 1K of memory expandable to 16K.

The ZX81 is also very convenient to use. It hooks up to any television set to produce a clear 32-column by 24-line display. And you can use a regular cassette recorder to store and recall programs by name.

If you already own a ZX80 The 8K Extended BASIC chip used in the ZX81 is available as a plug-in replacement for your ZX80 for only $39.95, plus shipping and handling—complete with new key board overlay and the ZX81 manual.

So in just a few minutes, with no special skills or tools required, you can upgrade your ZX80 to have all the powerful features of the ZX81. (You’ll have everything except continuous display, but you can still use the PAUSE and SCROLL commands to get moving graphics.) With the 8K BASIC chip, your ZX80 will also be equipped to use the ZX Printer and Sinclair software.

Order at no risk**.

We’ll give you 10 days to try out the ZX81. If you’re not completely satisfied, just return it to Sinclair Research and we’ll give you a full refund.

And if you have a problem with your ZX81, send it to Sinclair Research within 90 days and we’ll repair or replace it at no charge.

NEW SOFTWARE: Sinclair has published pre-recorded programs on cassettes for your ZX81, or ZX80 with 8K BASIC. We’re constantly coming out with new programs, so we’ll send you our latest software catalog with your computer.

ZX PRINTER: The Sinclair ZX Printer will work with your ZX81, or ZX80 with 8K BASIC. It will be available in the near future and will cost less than $100.

16K MEMORY MODULE: Like any powerful, full fledged computer, the ZX81 is expandable. Sinclair’s 16K memory module plugs right onto the back of your ZX81 (or ZX80, with or without 8K BASIC). Cost is $99.95. plus shipping and handling.

ZX81 MANUAL: The ZX81 comes with a comprehensive 164-page programming guide and operating manual designed for both beginners and experienced computer users. A 510.95 value, it’s yours free with the ZX81.

The $99.95 personal computer.

Introducing the ZX81 kit If you really want to save money, and you enjoy building electronic kits, you can order the ZX81 in kit form for the incredible price of just $99.95* It’s the same, full-featured computer, only you put it together yourself. We’ll send complete, easy-to-follow instructions on how you can assemble your ZX81 in just a few hours. All you have to supply is the soldering iron* How to order.

Sinclair Research is the world’s largest manufacturer of personal computers.

The ZX81 represents the latest technology in microelectronics, and it picks up right where the ZX80 left off. Thousands are selling every week.

We urge you to place your order for the new ZX81 today. The sooner you order, the sooner you can start enjoying your own computer.

To order, simply call our toll free number, and use your MasterCard or VISA. To order by mail, please use the coupon. And send your check or money order. We regret that we cannot accept purchase orders or C.O.D’s.

CALL 800-543-3000. Ask for operator #509. In Ohio call 800-582-1364. In Canada call 513-729-4300. Ask for operator #509. Phones open 24 hours a day, 7 days a week. Have your MasterCard or VISA ready. These numbers are for orders only. For information, you must write to Sinclair Research Ltd., 2 Sinclair Plaza, Nashua, NH 03061.


*Plus shipping and handling. Price includes connectors for TV and cassette, AC adaptor, and FREE manual.
**Does not apply to ZX81 kits

  1. GaryM says: November 1, 20118:59 am

    I once had a ZX80 and got paid for writing a couple of articles about it, so it was a financial win for me as well as being an interesting toy.

  2. Neil Russell says: November 1, 20119:15 am

    I bought the kit with its blistering 1K memory and getting it to work on a tv the first time felt like getting a message from space.
    I never had a Sinclair printer but I did later buy the 16K module thinking I’d never need any more power than that.
    About a year later I got a Commodore 64 because no one would ever need more memory than that!

  3. Richard says: November 1, 20119:34 am

    I remember buying the kit for $99.95 in summer of ’82, soldering it together, and getting a working computer. I also bought a 64K ram extension pack.

    The cassette interface was slow and error prone, and the membrane computer was awful.

    The ZX81 wasn’t so amazing for what it could do, but it was amazing that they managed to do anything with only four chips.

  4. Hirudinea says: November 1, 201110:25 am

    Horrible keyboard, pathetic memory but it was a computer and the price was right, and it was also cloned around the world!…

  5. Charlie says: November 1, 201111:27 am

    Hirudinea » Wow, a lot of those clones have even worse keyboards than the original!

  6. Toronto says: November 1, 20111:45 pm

    Didn’t it have a FORTH interpreter built in?

  7. Steve Smith says: November 1, 20112:25 pm

    I got the Timex-Sinclair version for Christmas when I was, I believe, 13 and was excited beyond words. Cheap and flimsy though it was, it was the best tool I ever ran across for learning to program in BASIC. (That may have partly been because, being the poor kid I was, I never had any money to buy a tape recorder to save programs. Whenever I wanted to run a program, I had to start fresh each time.)

    I sold the computer in a garage sale sometime in the late ’80s. Sure wish now that I had kept it.

  8. Hirudinea says: November 1, 20114:14 pm

    @ Charlie – Yea, check out the Russian Digra, Kvant-BK and Nafanja clones, you’ed get better keyboards on a cash register, no wonder they lost the cold war. 🙂

  9. Richard says: November 1, 20114:39 pm

    @Toronto: I’m sure the Sinclair ZX81 did not have FORTH built in. It only came with BASIC. I think you’re probably thinking of the Jupiter ACE, which had a similar (though I think independent) hardware design, and had a FORTH interpreter instead of a BASIC interpreter.

  10. JMyint says: November 2, 20118:35 am

    I lost my ZX-81 when I moved last year. I put it together as a kit in 1982 but I was smart enough to increase the RAM to 2K, that and I had access to some 4816 RAM Chips. Later I too bought a 16k memory module.

  11. Christian Berger says: November 3, 201110:45 am

    I have a ZX80 with the ZX81 ROM, making it a ZX81 without slow mode. Man compared to todays standards that was simply amazing. Only 1024 bytes of RAM, a lousy keyboard, yet it’s wonderful to use. You just type in your problem, press run and have the result.

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