Sinclair ZX80 / ZX81 / Z88 Forums

Good result :) as an aside, I bought a cheap later styled PSU (that matches the plus and 128K cases) that had an alarming hum to it when powered up. Turns out that some of the laminations on the transformer were loose and vibrating. I ran some UHU glue down between the gaps and now no more humming. ...

hmmm, very odd indeed. Bit like my Issue 2 weird colours problem, it's maddening tracking down what the problems are sometimes.

No expert, but I'd be leaning towards a problem with the diag card. Does the Retroleum ROM run in the diag card?

Lardo Boffin wrote: ↑Wed Dec 13, 2023 8:46 pm My name is Lardo and it has been over 4 weeks since I last bought a zeddy. Forgive me Sir Clive.

internal 16K has arrived, now to find time to get it fitted

How's this?

https://www.sellmyretro.com/offer/detai ... -48k-25951

Ah ha!

thanks for that, next time it's opened I'll reposition. Not sure if I mentioned this before but this example was taken apart and screwed into a frame or on the wall in it's time. I guess the previous owner put it on wrong ...

Question for you all - should there be an insulator underneath the heatsink where it screws to the pcb? I think so, as this was the root of my keyboard problems. Even after replacing the keyboard connectors and fitting another membrane I was getting no working keys when the case was screwed together...

Received the donor S2 motherboard. Swapped the ULA into my S2, same results, odd colours. Ok thinks me, my original ULA must be ok, or….. is the new one dodgy too? Put ULA number 2 back in its socket and tested the new S2 motherboard on the big telly as it’s not comp modded. Guess what? Dodgy colour...