Hi all,

I bought a Sinclair ZX81 on a garage sale some days ago for around 12 USD as a non-tested item as the guy said he had no wires to even try and run it. I have a couple of RF cable kicking about from my Atari 2600 and ZX Spectrum, so I have this basis covered.

According to the manual LINK it takes 9V 700mA unregulated (I’m not sure what it means) 3.7mm jack power supply. I have a 9V DC 1A jack power supply I bought for the Atari (it’s not an original one - a unbranded one) and I tried to use it, but to no success. Manual tuning my TV same as with Spectrum and Atari, and no signal.

I was wondering if maybe the power supply is not up to spec? I was thinking that maybe 1mA is too much to power it up? But I went online to look for an unbranded ZX81 power supply and they are running 2A so I’m not sure what’s going on here.

Is it busted? Or should I get one of those unbranded power supplies that say they are made for ZX81 to test it?

Thanks :)