I have powered it up, and managed to get it displayed on a Sony TV - see the "PRINT" picture, which is a picture of the output of this very ZX81. I haven't been able to test it beyond that, so cannot vouch for the rest of it.
Vintage SINCLAIR ZX81 COMPUTER IN BOX with Power Supply for Spares or Repair
Sinclair ZX81 Computer with Original Power Supply. UNTESTED.
Sinclair zx81 computer and Games Cassette **please read description**
Vintage Boxed SINCLAIR ZX81 Computer – Untested
Vintage Boxed SINCLAIR ZX81 Computer UNTESTED.
Sinclair zx81 computer boxed - Rare/ Vintage / Retro
