Sinclair ZX80 / ZX81 / Z88 Forums

I am VARTA, destroyer of boards!

Did you dump the demo ROM?

So just a keypress beep like the Atari computers do?

We've all done it at some time or another...

RAM chips go bad if you just look at them wrong, so I would first try replacing them.

Note that 4116 RAM chips will all fail nearly instantly and fatally without the proper -5v.

That's strange that the TC2068 needed a compatibility cartridge. When I had a TS2068, I exchanged the ROM for the TC2068 to gain back the Spectrum compatibility and it worked well.

It was pointless to make it incompatible with the Spectrum, because that meant it would have no software. Of course that made it 100% a market failure.

Yes, please let us know how you made one to this amount of detail by hand...

I had to connect pin 18 to GND (pin 12) when I adapted a 2732A on my PET, or else the machine was unstable. It would work sometimes and not others, depending on whether the case was up or down. Very strange... Yeah, if using a 2732 in place of a 2532, the unused control pin (be it /CE, /CS, /OE, /E...

I had to connect pin 18 to GND (pin 12) when I adapted a 2732A on my PET, or else the machine was unstable. It would work sometimes and not others, depending on whether the case was up or down. Very strange...