Today I heard a loud bang that tripped the circuit breaker in my server room. It must have been really loud because I could hear it 2 rooms away through 2 heavy doors and it was like a firecracker going off right next to me.
Long story short, it narrowed it down to one PSU from one of the computers. It smelled like burnt rubber and was really hot even after ~40 mins of being turned off when I finally got to testing it. All the rest of the tech was thankfully fine.
Its an old server PSU, like 10+ years old so not really surprised it blew up. Its a 800W unit made by HP but I couldn't find any model identification on it.
The weird thing is, I opened it up to really make sure this is the thing that failed but on the inside, it looks totally fine. Tested the fuse - all good, all the caps look good, no charring anywhere. After around 10 mins of looking inside the burning smell had faded away too. Still though, its the only thing that won't turn on. I got the rest of the computer it was attached to back up and running with a replacement PSU.
At this point I'm just curious - what could possibly create such a bang and not leave a trace afterwards?