On 6 Nov, 2004, at 17:39, Kevin Willis wrote: How do you know if your power supply is about to take the permanent dirt nap? My Gigabit G4/400 has on 4 occasions in the last couple of days just up and quit on me. It does not lock up or anything. I'll just be using it and it shuts off. Any thoughts on what could be causing it? Sounds to me like a heat buildup problem. Does the first shutdown happen after a certain time has passed? And, then the later shutdowns occur with shorter time intervals as you are working? That would indicate to me that there is a buildup of heat that is causing a fault to occur in the power supply unit. You might also check the wall circuit you are plugged into for continuity after running a machine for a time. If there is a GCI socket installed in that circuit, you may be getting false over-power signals from it that cause the circuit to shut off until it cools down again.