Sinclair ZX80 / ZX81 / Z88 Forums

Is there a way to get Paul's emulators working on a DivMMC/DivIDE since they can shadow the ROM into RAM can't they?

zx81-lapulga.png La Pulga - a simple concept perfectly executed. The design genius of using the time the key is held gives it a sort of analogue control precision. You play to perfect your technique because you can tell you get better with each play stint. It's an infuriating challenge that's as ju...

If I buy a donor machine, can I use an older ULA in a system that originally had the newer one with back porch?

Not long until people will be emulating a PS4 on a solar powered computer that fits inside a contact lens. Seems ridiculous now, but it's a logical progression.

I got the 2019-made Pure Retro ones on eBay, since the regular 2014 design from RWAP was sold out with no ETA for restock.

I trimmed the keyboard membrane tails on the surviving original keyboard I have and got it working. It is noticeably a lot more responsive than the reproduction. As in you only need a fraction of the pressure to trigger a keypress. I'd go as far as to say that most games are utterly unplayable on th...

I tried changing R34 from 220R to 470R and this also had no impact. So I guess it's ULA trouble.

The trimmer seems to have drifted now so all black pixels have ghosting, meaning I'll have to open the Zeddy up yet again.

I have decided out of curiosity to order a new composite mod from ZX Renew (£11) and give that a go, seeing as I was ordering an S-Video mod for Spectrum 48K.

Thanks for taking the time to write that out, very detailed. One other observation I've noticed is that the remaining 10K trimmer seems to drift with temperature, or perhaps it's the ULA drifting as it warms up. The trimmer we removed seemed to set the duration of the back porch in the h-sync pulse....

Thanks for the confirmation, I'll raise an issue on the project's GitHub.