I worked in a factory repairing Spectrum's way back when. The majority of the faults were memory or the PSU blown up by the power drain of the faulty memory. The CPUs were blown up by the expansion module being pulled off while powered up. Each bench had an engineer, a solderer and a tester bashing through repairs day after day. We would each get £10/day extra if we repaired 100 in a day! You quickly learned which RAM chip needed replacing just by looking at the screen. Happy days 🙂 Glad to see your on your way to get it fully working again.
I've noticed you have shaky hands because my uncle also suffers from it When I was a kid, I remember somebody was playing one of these & was playing a game using the keyboard. I knew he had a Kempston joy port adapter to plug in the back, I slotted it in the back, while he was still playing, it sounded like a party popper going off, then I saw white smoke & burning smells was rising up from it. The screen went back to snow static. I should be arrested for murdering a ZX Spectrum, I'm so sorry guys!🥺😢
Hell ! can you help ? i own a zx spectrum sinclair 48k that doesn´t load the games. They just get errors when first game screen opens or crash during the doalings and green little squares on some loading drawings. I inserted that to check the upper RAM chips : PRINT PEEK 23732 + 256 * PEEK 23733 the value result was wrong it was 32863 instead of 6553 »»»» I tested all the 8 upper RAM chips group on the board below (right side not the logical ones) using a fully working sinclair 48k and all 8 are good.
Hey, sorry for late response - I rarely look at this account. Ok, so a couple of things to check, I'd have a look at the multiplex chips the 74LS157 / LS00 etc.. it could be that they are weak or failed. Check that the memory is the correct type for the jumper settings, and finally if you can, swap the ULA and Z80 from a known working one. Hope that helps. D
I can't access instagram. Every time I try it tells me that I need to set up an account to continue. How many social media platforms are needed for modern life? It is bad enough having a faecesbook account without having several more clogging my system.
