Question Help, gpu no video input in one of my systems

[Helpmeplease345]

Hi guys, I have a bunch of dell optiplexes and I like to stick in a gpu and sell for some profit. One of my systems it seemed to work perfectly with the graphics card. Then I just had to swap out the power supply. When I plugged in a power supply I got second hand, it didn't turn on so then I swapped it out with a new power supply. But now there's no video input from my gpu. The thing is, everything else seemed to work absolutely fine, and when I use my motherboard graphics, it turns on like normal. Is it possible that the second hand psu only fried my pci slot and nothing else?

 

[Barty1884]

Patience, young grasshopper.

Which PSUs? Which GPUs? Which Optiplexes?