Sinclair ZX80 / ZX81 / Z88 Forums

Thanks Mark, I'll probably try to pick up an Ram Test burned EPROM. I wondering if it could possibly be a fail with the RAM address decoder? on the toastrack this a ZX8401 See 2 of the white border black centre fails on this page (two +'s IC3 & IC4) http://hardware.speccy.org/reparar-i.html Also I m...

So I have a white border with a black square that remains (most powers ons, although occasionally its all white with the odd coloured block also every 3-5secs the picture 'twitches' RGB out SCART) I suspected a RAM fail and I tried to run a RAM tester from divMMC https://github.com/brendanalford/zx-...

Thanks Rich, Yep the pull up was omitted and now in place its heart yet beats! Thank you! Now its White border with black paper plugged into SCART I see occasional screen twitch flicker. On SLAM an impressive job indeed, only that I found no documentation. This would have saved a lot of head-scratch...

Hi Everyone, I am trying to coax a Spectrum+ 128 (toastrack) back to life. The symptoms: Power on I get a Black border (likely indicating cpu was faulty or a clock issue) and black and white bars inside. Sometimes clean black / white 'bars' occasionally with odd bits. What I checked: I checked for 3...