XPS 8940, power issue, will not power on

do a BIST of psu.  if psu fan does not spin, even if psu green LED is on, that is a failed BIST and psu should be replaced.

@redxps630​ Thanks for the response.  Unfortuanately, this PSU does not have fans and does not have the BIST button - just the LED.

Re: does not have the BIST button - just the LED.

1. Turn off your computer.
2. Disconnect the power cable from the PSU and wait for 15 to 20 seconds.
3. After 15 to 20 seconds, reconnect the power cable to the computer.
   • The LED light should turn on for 3 seconds and then turn off.
4. If the BIST LED turns on, your power supply is delivering power to the computer.
5. If the BIST LED does not turn on or the PSU fan does not spin correctly, your power supply is not delivering power. Disconnect and reconnect the power cable and try again.