Hi Gargantua your advice helped me in resolving a black and white issue with one of my faulty american super nintendos. i noticed some strange behavior when turning the clock screw. So to resolve my black and white issue i removed the NTSC crystal and replaced it with a new one and the system now works perfectly. im wondering if replacing the crystal will resolve colour issues with other faulty super nintendo! the crystal i used was 21.47727 hz crystal oscillator, they are very cheap to buy on ebay think i paid about $1 for 10 shipped to australia. hope this helps other that might have this video issue.