Sinclair ZX80 / ZX81 / Z88 Forums

A warm welcome mate.

Thank for the update. I have an old ZX81 PCB not doing anything. This thread has opened up a couple of options for me.

Cheers.

That's a very nice piece of kit you have there. Certainly someone's labour of love. They obviously took a great deal of care and pride in it when they built it. Nice to see kit like this ending up in a good home. As regards the Prom chip, perhaps it was originally from something like a Memotec 64K R...

Fantastic, hope you get it sorted. Certainly its something l might need to do myself as my ZX80 came without a case and the protective cover was half hanging off the EPROM's quartz window. Fortunately in my case I've collect all different sorts of EPROM programmers as well as job lots of EPROM's off...

Don't know if Grant Searle's ZX80 page is of any help. He shows how to modify the setup in order to use a different EPROM. I think it also has links to the ROM images.

http://searle.wales/

Kind regards
Andy

Thanks for taking the trouble to produce a circuit layout

Good reminder. I had forgotten all about that. This info will come in handy as I'm using an old 240VAC/12V DC camping TV/VCR combo for my retro computers, until I can get all my stuff up and running on RGB/VGA adaptors.

Again, thanks for the reminders.

I think it's unlikely you'll find a brand new item, unless you mean new, old stock, where the box has never been opened. There's several vendors on eBay selling ZX80 and 81 clone PCB's. These require you to source your own components and in most cases flash your own PROM/EPROM. I'm not sure that the...

Part 2 Replacing IC 6 For some reason the 74LS157 (IC6) has a crack right across the package. The entire package is cracked and broken free from pins 6 to 11. https://live.staticflickr.com/1902/45796229202_fe221b65ad_4k.jpg This isn't ment to be a tutorial on soldering or removing broken devices. A...

Daeve wrote: ↑Tue Nov 05, 2019 10:00 pm I’d love to pick up a reasonably priced ZX80 and learn to repair it.

And that's the big problem. There's so few of these in circulation now that working examples are horrendously expensive.
And chances are that most of the broken or faulty ones were disposed of years ago.

Regards
Andy