Sinclair ZX80 / ZX81 / Z88 Forums

From 32768 downwards is the Z80 stack that's definitely used once the Z80 runs Ah, the stack is up there ? Thats why I'm seeing changing numbers. Ran a test of memory from 18000, up to 32768 and it was only the last few bytes that didn't play so the memory is probably ok. But it looks like a good i...

Hi I have a ZX81 issue 1 with the 622 ROM and the classic MEMOPAK 16K and I think I have a problem with the memory (3d monster maze wont run !) When I hackup a memory test, locations from 32725 to 32768 seem to be faulty. But I can't find a straight forward memory map to check if this area is being ...

Hi everyone. Just getting back into 80's computers and trying to put together a collection of the machines I wanted at the time. Had one of the first zx81's back in the day but gave it away many years ago. I then ended up working in a nuclear power station, writing reactor control software in CUTLAS...