Sinclair ZX80 / ZX81 / Z88 Forums

As well as the offical Sinclair 16K byte RAM pack, there was the 2K/3K/4K ZX80 RAM pack (memory size depending on how many SRAM chips were fitted in it) that would work with the ZX81. Plus many third party manufacturers that produced various RAM packs. One of the best known for more stable RAM packs...

Hello and welcome to our forum Juz571!



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Mark

Glad that you are now all sorted

Mark

The ZX81 uses mode 1 (IM 1) so does not care about what is on the data bus. Hence you don’t need to worry about /M1.

Mark

Lots get caught out by the UK700 producing 12V to 16V when off load, and 10V to 12V when on load.

Good that you are making progress.

Mark

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Nice set of 1980s computers and extra hardware

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Mark

Hello and welcome to our forum Staffan!



I hope you enjoy this forum

You are welcome to ask questions!

Mark

The cursor is not likely to be off-screen, more likely is that the video contrast (voltage) is wrong. Hence the K cursor may be there, just not visible. If the picture size was incorrect, I would expect a rolling image, due to incorrect sync. Keep in mind that the transistor type composite modificat...

Ahh, I was going to reply the other day, must have forgotten

As the Opus also uses it's own ROM, has the previous owner fitted or modified the MF1 board with a switch or some other method to disable/prevent it's ROM and RAM from being paged in?

Mark

Hello and welcome to our forum Luke!



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Mark