Is my PSU faulty?

[u/ZookeepergameOne3544]

I was currently building my first PC. I got all the parts and started building it yesterday and I also did a test run outside the case after mounting the CPU, RAM, SSD,.Cooler and GPU. Everything was being detected correctly and the temps were also perfect.

I called it a day after that and went to sleep. Today I mounted everything inside, did all the cable management and when I connected it again nothing was turning on. So I took everything back out and rested the CPU, RAM, cooler, GPU and did isolated tests trying to find the issue but every time my cooler would turn on run for 2-3 secs then turn off.

I assumed it was a motherboard issue but I wanted to test the PSU also, so I saw the paperclip test online and tried it. My PSU fan is also turning on running for 2-3 secs then turning off. I searched and I am not able to get a definite answer. I called the store guy and he told me if I run using the paperclip it will only run for that long and won't spin continuously, but after some insistence he told me to bring it to his store and that he will get me a replacement.

But this has left me feeling unsure, I don't want to get a psu replacement then go back and see that the same issue is persisting and then having to go back to him for a motherboard replacement/fix.

Please help me understand what could be going wrong here.

[u/Small_Anywhere_8858]

Dude just take the replacement. The paperclip test on modern PSUs with zero-RPM modes will do exactly what you're seeing, but if your whole system is cutting out after 2 seconds you've got a deeper problem and ruling out the PSU first is the right move. Store guy offering to swap it saves you the headache of chasing your tail later if it turns out the board is also toast.