I'm having an issue with the PSU cooling fans running at their max rpm, 2800. Hardware Monitor shows that the PSU temp sensors are disconnected. Last Monday I changed the CPUs from dual to quad core units, from 5160s to 5365s, so it's possible that I caused a connector to pop off, if they're under the main dual cooling fans. I can't seem to locate that info, though, and before I disassemble things again, I'd like to know if those connectors are in the area where the PSU connects with the mother board. Does anyone know of a photo of diagram illustrating where the PSU temp sensors connect to the mobo? This is a September 2007 Mac Pro build, with the ROM upgraded to 2,1 status, running Lion 10.7.2, and plenty of RAM. smcFanControl is installed, but won't control the speed of the PSU fan now.