Regarding heat, you have to be careful with those cabinets. Not sure where the PS3 vents are, but don\'t forget to take the side ventilation into consideration, and do you have more equipment stacked right above/below? In my cabinet I leave a few rackspaces of open air above my 360, as well as having the open front and back during use, and it\'s mounted in an open-top shelf that has ventilation slots on the bottom.
For your problem, though, I\'ve had regular DVD disc\'s skip on me despite being new, just because of an accidental thumb print. I doubt you\'d miss that, but if you haven\'t checked, that\'d be an easy something to look for.
