Replaced PS4 Pro power supply and still no light and no beep.

I’m trying to fix a PS4 Pro that I picked up recently which had a bad power supply from roaches. I bought a replacement power supply, tore everything down and gave it a really good cleaning. After getting it mostly back together, I pressed the power button, and everything looked good. The light came on and the fan started spinning. At that point, I realized that in my eagerness to test it out, I hadn’t yet installed the HDD. So I unplugged it from the wall (which was probably not ideal), installed the HDD, and… nothing. No more light. No more fan. It basically was back where it had been when I picked it up.

I’m not sure what the best thing to try is. Is there a good way to tell if my power supply is functional? Are there some steps that I need to take to reset it? Why would it work the first time with no HDD and then just stop every time since? Thanks for the help.