Hey guys, I know this isn't technically monitor-related but its video-related

And it's not arcade either.. if it needs to be in a different section please move it by all means.
Basically for the past few years I've had a Toshiba hdtv (lcd) as my main television, instead of a crt. It's a fine piece of machinery but I noticed on a lot of my old consoles, the screen isn't too happy.
It's got an RGB scart input, but some of my consoles are sending signals it just doesnt like through the scart. Does it with my n64 and especially my megadrive, the screen will jump up a down by about 5 pixels every few seconds which is highly migraine inducing!
I plugged it in through my old VCR and that helped but it's not that happy with the vcr either so it's not much better. I should also mention it happens on the same pieces of hardware (megadrive etc) through RF socket as well. I know the scart works fine because it works great with my dreamcast/ps2/xbox360, what I was wondering is if there was some simple circuit I could build to take the signal from my megadrive and amplify/refine/stabilise it so my hdtv is happier.
Now the only crt's I have left are in my arcade machines and my megadrive is lonely

Cheers for any info
