Happy 30th Birthday: Sinclair ZX81 Personal Computer

  • Released 5 March 1981
  • £49.95 kit form, £69.95 ready assembled
  • Sold more than 1.5 million in its three-year run
  • Manufactured by Timex in Scotland
  • Sinclair BASIC operating system
  • 9v DC Power Supply
  • Z80 CPU running at 3.25Mhz
  • 1k RAM (64k max, of which only 56k was useable)
  • Monochrome output on VHF television
  • 64 x 44 pixels graphics mode
  • Weighed 350 grams
  • Abysmal touch-sensitive keyboard (although it was an improvement on that of the ZX80)
The original press advertisement. CLICK TO ENLARGE.


You’ll all probably remember Saturday mornings in early 1981, running down to WHSmith to have a go on the new computers that had just arrived, and doing this:

And then we’d all giggle with glee as the word BUM scrolled across and down the screen.  Remember kids, that semicolon at line 10 was VITAL.


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