Why does it not turn on sometimes

I had just gotten this 360 slim from a friend, and he said that sometimes it would turn on, and sometimes it wouldn't. I think it's something up with the rf board, but he said it's the ribbon cable that goes into the rf board. So I took it apart, and I saw nothing wrong with anything but the rf board connector where the ribbon cable goes in looks a bit lifted. Like it's not being held down a few centimeters, and I'm curious to know if it's the ribbon cable or is it the rf board, or is it both, by any possibilities.