My MacBook Pro suddenly stopped charging (the light first started to not go on consistently while charging and now won't even go on). It looks like one pin on the MagSafe on the computer is fried. I took the computer apart to change the part with one bought off eBay, but it looks like I bought the wrong part (the one I bought seems to be for a unibody, I have the generation earlier). I think the part I need is Apple 820-2274-A. Is this a common problem? And, does anyone know of a reputable source for a replacement part? Or, do you think Apple would exchange the part if this is a known problem? Thanks for any help.