Unfortunately, this turned out to be not as easy as I hoped it would be: the ZX-81 was built to “minimalistic” standards – to be polite! There is no LED or light to indicate if it is switched on or off, there is no sound one can test to see if it works… there is simply nothing but the picture on the TV Screen and – if you don’t have that – no other way to tell if the system is operational or not.
The problem with my ZX-81 is that the box did not contain the TV Connector cable. “Well, fine, I just use the antenna cable of my TV” was my first though and it quickly turned out to be naive: my cable does not fit into the connector of the ZX-81!
So here I am, not knowing if the computer I bought even works, but curios as hell to learn if it does or not! I decided to “tweak” the connection to the TV a little but – putting a TV Antenna Splitter “the wrong way” into the connection between the computer, just to see if any sort of signal come out of the little black box.
And yes, it does: the TV produced a clear (but not stable) image of the ZX-81 Command Prompt on UHF Channel 36 – so now that I know it does actually work, I can start wondering about how to hook it up to either the TV or – preferably – a modern LCD Monitor.