Okay, I have one of those 4-way scart boxes that allows you to connect a number of RGB scart devices to you TV.
I purchased one of these in the past, and it would not carry an RGB signal, only composite, so I got poor picture quality from my DVD player and GameCube, which were connected to it.
So, I had a hunt around and found one that would carry RGB signals. Strangely, this had to have an external power supply, but it worked great. Then I decided that it would be worth buying an RGB cable for my GameCube, rather than using the normal 11 pin composite one you get with it.
This greatly improved the picture quality of all of my games. However, there is a big problem with it. Whenever a game seems to show a lot of bright colours or plays an in-game movie, the picture completely messes up and jumps all over the place, like a picture that is not tuned in.
It's something to do with the 4-way adaptor, as it does not cause a problem if I directly connect the GameCube to the TV, with the new lead.
I can get my money back for the adaptor, but what do I need to look for when buying another one, that will stop this problem, or could it just be faulty?