I've got a Performa 630 that was working until recently, and now it doesn't power up anymore. I can sometimes get it to power up, but most of the time there is simply no response. I suspect the power supply is at fault, as it always had and still does have a whine to it when plugged in. Would this be caused by capacitors in the power supply? As far as I know, neither the logic board or the power supply have ever been re-capped.
