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For questions regarding computers made by the Sinclair group of companies: Sinclair Research, Sinclair Radionics and Science of Cambridge.

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1answer
198 views

Timex Sinclair 1500 and screen “jail bars”

I have tried to eliminate "jail bars" on the screen after UHF mod to video out (based on that: http://zx81stuff.org.uk/zx81/ts1500_video.html) by adding 460uf 16V capacitor between +5V and GND but it ...
6
votes
1answer
366 views

Cambridge Z88 Production Run

While this is not a technical question per se, I finally found something I have no idea and couldn't find any answer online: How many Cambridge Z88s were made and/or sold? As it's related, a sub-...
7
votes
2answers
448 views

Why does this BASIC program generate variables for the numbers 0 to 4?

On pages 150 to 154 of William Tang's (1982) Spectrum Machine Language for the Absolute Beginner, there are these lines of code. (Note GOTO 9000 is the first non-REM statement in the program). 9000 ...
22
votes
6answers
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ZX Spectrum tokenisation

The BASIC used in the early ZX Spectrum (and also its ZX predecessors) had this weird thing where every single BASIC token was printed onto the keyboard, and for example PRINT or LOAD were entered by ...
29
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2answers
4k views

Why did Sinclair choose the Z80 for its range of home computers?

The Sinclair computers are known for their low cost compared with other computers that were popular in the early 1980s. This is why they had membrane keyboards, or that rubber stuff in the case of the ...