Sinclair ZX80 / ZX81 / Z88 Forums

Hello! I recently got my hands on a Spectrum 48, issue 4B. It's a pretty beat-up looking machine, must have seen heavy use. The keyboard connectors were broken, wasn't connected at all. The VR was also broken (the pins had broken off near the pads). I replaced the VR, and now the speccy turns on. The screen shows a weird pattern though, I need some help in figuring this out. I think there are some recognizable characters like "B" and "R" and "K" in the pattern, and the pink vertical lines between the character lines blink. Where should I begin to check this issue?

Greatly appreciate any help with this, I do want to get it working!


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There are a few quick checks here but I’m not sure what you are seeing is in here:

https://spectrumforeveryone.com/feature ... nja-style/

Doubtless one of the hardware gurus will be along shortly.

There is also a welcome area to say hi! viewforum.php?f=22

Lardo Boffin wrote: ↑Sun Sep 26, 2021 9:02 am There are a few quick checks here but I’m not sure what you are seeing is in here:

https://spectrumforeveryone.com/feature ... nja-style/

Yup I did go through this, but am having a tough time understanding the part about the ULA's interpretation of the memory attribute data. Is there a way to figure out what could be the most probable failed ICs? The patterns on this page and the one I am seeing doesn't seem to even somewhat resemble.

Lardo Boffin wrote: ↑Sun Sep 26, 2021 9:02 am Doubtless one of the hardware gurus will be along shortly.

There is also a welcome area to say hi! viewforum.php?f=22

I dropped a note on the welcome group, good to be here Hope to get some leads from the veterans here!