Re:  I think the psu has failed to prove that, you need to test system using either a working Dell proprietary psu, or a standard 24/4 pin ATX psu w a 24 to 6 pin adapter (from moddiy or CoMeap).   Re: Is my PC psu overburdened or was the failure just a fluke? more likely the latter if it has indeed failed way ahead of expected life span  If you can definitely prove psu has failed (not just think), then you can buy genuine replacement OEM psu on line.  Not sure if Dell can sell you a replacement spare part but you do not have to buy OEM part directly from Dell (usually more expensive than retail for exactly the same model).  If I were you I would also consider 24 pin 500-750w SFX psu w adapter as an optional psu upgrade.
Hello all, I am having an issue with my XPS 8940. I have the i7-10700 cpu, 32 gb ram, nvidia rtx 2060. I have the 500w psu and I added a sound card and a better ethernet card. I have had the pc since August 2020. Yesterday morning everything was fine, but by the afternoon the pc would not power up. The BIST light does not light up at all. I tried isolating any issue, removed all cable attached to the motherboard and graphics card. I also removed the cmos battery and tried that. Nothing. I think the psu has failed, but haven’t contacted Dell support yet. The pc is out of warranty. Is my PC psu overburdened or was the failure just a fluke? I have owned many Dell PCs and have never had a psu fail on me ever. Will Dell even sell me a replacement psu? Thanks for any help.
XPS 8940, PSU dead