To run 4X faster, but then the display gets jerky. The fix? Don't update the displayĪs often - the SLOW and FAST commands determine the video display rate. Updates the screen at the same time, slowing the program speed. To perform all of the tasks that are required of a computer, which means it executes the BASIC program and The computer is composed of only four IC chips, and there are no video chips or co-processors. The video display is your TV, in B&W only, there is no color support. Tape the RAM pack to the computer to prevent loss of contact due to accidental movement.' What can be the problem?'Īnswer: 'If the 16K is causing your computer to 'crash' after a few minutes of use, then you should try the following:Ĭlean the contacts by vigorously rubbing the electrical contacts on the printed circuit board withĪ pencil eraser. Question: 'My computer seems to be 'crashing' when I use the 16K RAM module, even though it never does

Very popular, although the non-secured edge connection could easily get dirty or come loose,Ĭrashing the system and losing your data.įrom the Sinclair ZX81 Operating Supplement: There is an expansion port on the back, mostly for memory expansion. Users hacked into their system and added their own 'real' keyboard, external to the system. While easy to cleanĪnd water resistant, it is very difficult and slow to type on, because you have to press hardĪnd very deliberately to use the tiny, closely-spaced keys. The keyboard is a 'touch sensitive membrane',Ī flexible plastic surface with the actual switches under the surface. Same speed as the ZX80, but it has a better BASIC programming language and is cheaper to produce, due toĪlthough cheap and quite popular, the ZX81 was, well, cheap. The ZX81 has the same microprocessor and runs at the Compared to the ZX80, the ZX81 was much cheaper,Īt only $99.95, the first computer for under $100. One year later, they released the new and improved ZX81. In 1980, British company Sinclair released their ZX80 computer for $199.95.

Sinclair basic