So this all started with my newish desktop build deciding to not turn on. I have the tool to test most parts and determined it was either the MB or the processor, sent in the processor first (intel pentium G860) and got sent back a brand new one. Computer still didn't work so I sent in the board next (ASRock z77 pro4). Just got it back today and put in. First thing that happened was a small trail of smoke came out near the 24 pin. I quickly cut the power and decided to try it with another power supply. And got exactly zero results. Fans turn on for half a second but that's it. So after being without my computer for well over a month I'm at a loss. Any help?
Sounds like there was some kind of a short between the board and PSU, and most likely the motherboard has been damaged as a result. If you're really lucky, it was just the PSU connector that was damaged and a new PSU will fix it.
I tried it with a different power supply and got the same results without the smoke. So I guess I'll RMA the board back to ASRock. Oh so not happy to do this again.
You can try that, but don't be surprised if they refuse it. Essentially it was your PSU that likely damaged the board, it wasn't some sort of defect with the board, so ASRock may well decide that you'll have to pay for a replacement.
on the the new power supply green wire it and with a volt meter check the outputs. look at the pin that fried on the mb and line it up with a stanard atx pin out it tell you the voltage on that pin. make sure your new ps output is within spec. also check all your cards and ram for bent pins and or broken parts. if it was not a bad power supply then something made a dead short. (wrong screws or no standoffs).