Sinclair ZX80 / ZX81 / Z88 Forums

I take my hat off to you Andy and your vision for that poorly zeddy brought back to life is memorising.
Is that a re-designed ula on that atmega chip I see.
Well done Andy well done

Hi there
I had the same problem and it turned out that the ram was at fault
The kursor K is static until you type something.
Hope this helps.
Kim

Hi all I got the zxmore board from Pokémon and I must say that the board and contents are second to none. My son has built the board and when he told me he couldn't get it to work I had a look. He has a trace missing where the 47pf cap is on pin 4of the clock and the via. He has also lost the pad at...

Yeah thanks Pokémon.

Hi Gabriel

Now I'm no expert but sometimes an incompatible TV would display a white screen with nothing else, or makes the k cursor do weird things
I've had this sort of problem myself.

Hope this helps
Regards
Kim

Hi all
Hi Pokémon,
I have received my zxblast and it is amazing. The letter you put in the package i have missed placed, what i could do with is the update address if possible.
It is a well thought and well engineered piece of hardware that the ZX81 needed to survive another 30 years.
Thanks
Kim

Hi matey
Have you tried booting your zx81 with the 16k ram pack on
I think it could be the internal memory at fault at a guess.

If it does boot to the K with the ram pack attached then you have your answer......

Zxkim81

Hi all
Is it possible to buy a switching regulator in stead of the 7805 regulator as mine is running very hot so
It's only a matter of time before she blows.

Thanks
Kim

Hi all I'd like to update you on my zx81 keyboard anomaly. Well i ordered a load of diodes, resistors, electrolytic caps oh and a new keyboard. Then I ordered an oscilloscope and a logic probe. I used the oscilloscope on the ula and found everything ok. Changed the resistor pack on r3 changed diodes...

Oh i bought one too
Kim