I recently replaced the power supply in my Dell XPS 400. Ever since doing that, the fan sounds like a jet plane reeving up for take off. It seems to be varying in speed and when it is running the fastest in whines a high pitch sound. You can hear it all over the house. Any suggestions or recommendations for a remedy?
Besides replacing the power supply, have you made any other changes to the XPS 400?
While installing the power supply and the power connectors, you may have dislodged a connector, or component, have you tried checking everything inside the case, eg power and data connectors of all the drives, memory modules, fans and PCI cards are still properly connected, by removing and reconnecting them?
Check that heat sinks are still firmly connected to the motherboard and that there's no dust build up on the cooling fins, fans and in the front panel air intakes.
Also check the status of the four diagnostic lights on the front panel?
I would suggest you to clean the system’s air vents. As the power supply is replaced, you may reseat the system fan. Please ensure all the cables are connected properly. You may reset BIOS to defaults. Please follow the steps below:
Hope this helps. Please feel free to reply for further assistance.