I was swapping cases between my HTPC and server. Components were all in working order when in old cases. Swapped all the HTPC components into the other case and it powered up and posted just fine. Got to the server and plugged the power supply into the motherboard and plugged in the case switch and tried to test it to make sure it would power up. Green light on the mobo was on, but hit the case switch and nothing. Granted, the only things that should come on is fans at that point, but CPU and power supply fans were both off. Tried plugging the reset switch into the power pins. No go. Tried shorting out the pins, nothing.
I found this link: How To Manually Test a Power Supply With a Multimeter
to test my PSU with a multimeter. Shorted out the 2 pins it said and it turned on. Plugged it into a case fan to make sure. It was on. Tested the relevant motherboard plug pins. All good.
Plug it back into the mobo. Nothing. Pull the mobo out of the case and plug it all in. Still nothing. I don't have another motherboard to test out the power supply, but I can pull apart the HTPC and test the server mobo on the HTPC PSU. But it sounds like I fried the motherboard right?
Anyone else had a similar problem?