I was wondering if anyone could tell me why my nes has poor picture quality? I noticed this the other day when my buddy and I were playing contra on his nes. His was nice and crisp and it had better color. I then put it into my nes and the colors where dull and fuzzy. I just recently replaced the pins and I know my friend has had his replaced. I have also cleaned everything multiple times. The only difference that I can say between the 2 systems is that I use RCA to hook it up and he uses the RF switch. Could that make that much difference? I thought that RCA would be better quality. I will take a picture the next time I am over at his house which should be today. I will post the two pictures to show the difference. Also I was wondering what the slot on the bottom is for?(the thing that is covered up by the removeable plastic cover)

Thanks