My latests projects have been on modifying my zx81and my Atari VCS, I started by modding my zx81 after trying out the rf output and not getting a great deal of picture, a poster on http://fignition.proboards.com suggested this mod, and I got great results.
So bouyed by my new found confidence I looked at possible ways of modifing the Atari, after a search on the web I foung this site to be the best source of help, however My Atari is a Sunnyvale 1978 model, and has a red pcb, so the location descpripiton of all the sites I looked at were different to the pics I viewed on line.
The Circuit I used was changed to a lower resistor ladder plus I included resistance at the chroma input as I got a very blured image with only a capacitor in line.
I also had to by pass the 10k resistor completely for the picture to display at all.
the Carlos version.
Many thanks to David Savery from his blog at
here are some of the results