Sinclair ZX80 / ZX81 / Z88 Forums

Found some more minor inconsistencies. According to the Assembly Instructions both RAM chips were different. Found the same thing for the 1-3K RAM pack. The chips were referred to as 2114L and 2114L-1? But with the additional note that "*In case of supply difficulty may be same type as IC4". Does an...

On another note I bought some caps for the zeddy and the 1uF cap has no obvious polarity markings (again, I know). Any ideas or have I wasted a few pence? Usually the shorter lead is the "minus". And perhaps that is what the (M) marking means in the second picture. But... don't quote me on this one...

Hi Mark, I just left a comment about your vacuum forming idea for the case. What a coincidence :-) Great idea btw. But yes, I figured this would be the right forum! Already found quite some info that helped me to complete the schematic. I was hoping Grant Searle is still reading this forum. I tried ...

Oh wow Mark, that sounds interesting! I'm in the process of redrawing the schematic and PCB layout in my CAD program so I have a set of gerber files that I can send of to any PCB manufacturer. So I could use one of those vacuum formed enclosures! Do you plan to sell these? Just an idea... I know the...

I'm in the process of redrawing the schematics and PCB layout of the ZX80 in my CAD program. I know this has been done before and I have seen the great job that Grant Searle did, creating foils so you can build your own. But I've thrown away my UV exposure box and chemicals as soon as professional P...