What happens if you put your finger on the /ROMCS signal ?nama wrote: ↑Sun Sep 03, 2017 9:32 am I just built up Marks circuit using a 74LS02.
Have a look at this...It's even more dynamic
https://www.youtube.com/watch?v=zg1Gymf ... e=youtu.be
Phil
Does it get more stable ?
I had similar effects on other hardware (ZX81 compatibles) and good solved with a 22-47pF capacitor between /ROMCS and GND.