So was the consensus that the old ATX PSU died? I've done the same thing with an Xbox one, worked fine for about a week or two and now I just get nothing at all unless I manually turn on the PSU with by shorting the PS_ON line to ground, when I do that though I get full fan and no ability to turn the Xbox on, it just makes an attempt at the on sound but doesn't actually do anything from there. All my voltages are reading correctly, but I can't seem to measure amperage in any capacity. I guess I'll jury rig another PSU to see if it's the issue. Was a cheap one from the road side anyway.