I'm playing with an Xserve 1,1 (2x2GHz dual core). All was going well until one day the fans for the CPUs and RAM stopped coming on. Everything runs as normal but, naturally, the heat builds up and things start to go wrong. Everything else is OK. I've swapped in a known-good power supply. I can't imagine that something could stop all the fans (they can apparently run at different speeds, if necessary) except a controller failure. Service Source doesn't tell me where the controller is; it doesn't even have a "all fans off" symptom. Does anyone have experience in this area?