Hi there fellow Atari enthusiasts! I'm new on here - this is my first post. Hopefully one (or more!) of you guys can help me with a slight problem I have with my 800xl. I bought it of evilbay recently, and it has a strange picture problem. The computer didnt have a rf cable when I got it so I purchased a cheap standard rf cable off ebay too, I hasten to add not an original atari item with the little switch box inline. The problem is weird, the screen that you get when you first turn on (standard blue screen with "ready") is 100% fine, but when you play a game the screen is sometimes distorted when the screen flicks from one scene to another, sometimes it goes black and white too. Only when playing a game though - like I say - the normal blue screen is fine! Strange! So, what do you think guys? RF cable? RF modulator? power supply unit? Any suggestions would be gratefully received! many thanks!