Sinclair ZX80 / ZX81 / Z88 Forums

I was programming some type ins from a magazine last night. I left it on all night and realized this morning that it wasn't responding. I removed the power and put it back in, and nothing. No lights, no screen, no reaction?
It was working fine until last night, no problems whatsoever.
Is there something I can try?
I know a local person that repairs zx81's, should I just send it in without trying anything else?

I just found out something strange. If I move the PSU cable, the 81 comes back on, but a small movement of the cable, and it dies again. That means it's the PSU?
Should I try to make a new cable for the PSU or just try to buy another one?

Try any power supply with 9V DC on the middle pin.

mrtinb wrote: ↑Tue Mar 16, 2021 2:23 pm Try any power supply with 9V DC on the middle pin.

Can it be any 9V DC or do I have to get the ZX81 PSU?
Thanks.

https://sinclairzxworld.com/viewtopic.php?f=7&t=4041

This thread talks a little about the power supply. Try searching further in the forum.

Any 9V DC with 650mA or more will work. +5V on the middle pin.

It will even work with 5V power supply, but then an attached 16kB RAMpack will be destoyed, so that trick only works without the RAMpack.

Thanks!

I wouldn't recommend a 5 volt power pack as the linear regulator drops out at less than 7 volts and you won't see anything at all hence the general recommendation for a 7.5 volt minimum supply where this regulator is concerned.

Thanks for correcting me Moggy.