Does anyone know whether there's been a recent revision to the power supply for the 23" ACD? Display randomly won't turn on. There's lots of evidence in this thread on the Apple Forums that the problem is power-brick related, but a replacement brick from eBay didn't help me. I'm trying to figure out whether there's a newer power source available I need to try. The Apple thread seems to suggest the power supply has been revised . . . can anyone confirm, and if so, how might I get my hands on a new power supply (since my AppleCare is expired)?