Odd power supply issue

TheMagicGurneyy · December 6, 2016

Hi. So essentially I am stumped and looking for help from someone that knows more than me. I've been trying to help a friend upgrade his rig over the past month and he finally got an rx480 over black Friday. Fast forward to me snowing him how to install it and I brain farted, not remembering that his stock 350w PSU wouldn't have an 8 pin for the card. So we travel to our local Microcenter (praise) and get a smoking deal on a EVGA 80 plus rated 500w. We get it to his house but run out of time to get it running. I send him a bunch of LTT and other vids so he can do it himself when he can but after a couple days all he can tell me is, "it won't turn on". I go over there to diagnose thinking he just missed a silly noob thing, nope he did everything right. So basically I tell him it's either the PSU or something else either on the motherboard or the board it's self. I take out the 480 and try using the old power supply. It turns on without skipping a beat. So it's not his motherboard or any of that hardware. Then I try the new power supply without the rx480 and still it doesn't turn on at all. So it's not the 480 either. Then I take the new EVGA PSU home instead and try it on one of my own rigs. IT WORKS WTF. So it's not his motherboard, ram, the PSU, or literally anything I can think of. The ONLY difference between the other rig I tested the PSU on and his is that the other one uses a 20+4 connector for the main motherboard power and my friends build is just the 20 pin. WHAT COULD POSSIBLY be stopping his rig from getting any kind of power from the PSU?! I'm so lost for any sort of answer right now and have no clue what to do.