My ZX81 (Sinclair/Timex 1000)

[SilverWingedSeraph]

Hi EEVBlog Forum! I just got a Sinclair/Timex 1000, known in the UK as a Sinclair ZX81. It was new-in-box, and is an absolutely beautiful bit of 1980s kit. HOWEVER, I would like to be able to use it on a relatively modern display. I know it's possible to convert the RF modulator out to RCA mono video, but... how? Does it require an internal mod, or is it practical to build a demodulator?

Thanks for the help, and while you're thinking on the question, here: http://imgur.com/gallery/R0m4r are some photos of this beautiful machine!

 

[IanJ]

Google:
zx81 composite modification

Here's one example:-
http://www.zx81stuff.org.uk/zx81/ts1500_video.html

Ian.

[hendorog]

Hi EEVBlog Forum! I just got a Sinclair/Timex 1000, known in the UK as a Sinclair ZX81. It was new-in-box, and is an absolutely beautiful bit of 1980s kit. HOWEVER, I would like to be able to use it on a relatively modern display. I know it's possible to convert the RF modulator out to RCA mono video, but... how? Does it require an internal mod, or is it practical to build a demodulator?

Thanks for the help, and while you're thinking on the question, here: http://imgur.com/gallery/R0m4r are some photos of this beautiful machine!

Oh that is very cool. I started programming on one of those that we borrowed from a friend, that started the journey for me...

[SilverWingedSeraph]

Well, I FINALLY finished the mod! Turned out, the collector-follower buffer wasn't sufficient; I had to also put three 1N4148 signal diodes in series with the output. After that, it worked a treat, as Dave would say! Thanks IanJ for pointing me in the right direction.

I took photos all along the way: