Ken, a ZX81 ought to boot (if you can dignify it with that term) without the keyboard since it's just a switch matrix connected to a Z80 port. You should be able to get it to the K cursor. One problem these days is getting a compatible television since the '81's output signal is what one might call an approximation of a monochrome TV signal. As I understand it, modern LCD TVs with a PAL input normally struggle. Hopefully though that's not such a problem for someone on this forum