Power supply wasn't dead after all

I post this because I'm an idiot, and I want to spare someone else from making the same mistake. So please don't rag on me too bad.

I got a PSU CORSAIR|CMPSU-650TX 650W RT for a new build. I plugged it in and flipped the switch and got nothing. I took out my multimeter and found no voltage coming out of it. Okay, you're cringing. I know. So I called Newegg and got an RMA and exchanged it for the same. The same thing happened. Then the lightbulb went off. I hadn't plugged anything into the mobo yet.

Once I got everything plugged in, it worked, of course. That is after I plugged in one (but not two) power supplies to the mobo and turned the system on, only to have my heart sink. Thanks to Tom's Hardware sticky post about diagnosing dead new builds, I realized I needed two power supplies to the mobo. Now my new ASRock X58 Extreme, i7 9200 build works like a charm.

So if anyone's searching for dead power supply and they made the same mistake, hopefully they'll find this. Newegg, if you're reading this, I'm sorry.