Wintermute_BBSToday, I picked up my loose ends with regards to the #Czerweny #CZSpectrumPlus, the #rare #ZXSpectrumPlus clone from mid-1980s #Argentina.
Since I was unable to remove the ICs myself (did they use "nuclear solder" back in the day?! Those ICs sat tight in their holes) I asked a friend who had a friend who was up to the job and very professionally removed these at his workshop.
So today I soldered sockets in place and prepared a #Diagnostic #ROM in order to find out what the problem is. Looks bad.
I have already replaced all "lower" RAM chips with new ones, leaving the "upper" RAM as they were.
However, given that *all* memory seems to be faulty, I now expect the #ZX8401 to be the problem. So now I need to get either one of those modern drop-in replacements or start hunting a real one ...
On the up side, video is working and the beeper is beeping. At least.
Cristián_Rojo