So I bought and installed a Corsair RM850X power supply. I removed all the existing power cables and used only the new ones that came with it to connect the motherboard and peripherals and drives.
Unfortunately, unRAID won't boot with this new power supply, so far anyway. I connected the power plug to my UPS, flipped the power switch on the PSU to the On position, and the lights on my motherboard come on. Then I press the power button my PC. My CPU cooler fans spin for a moment but then stop and the PC doesn't boot.
I tried it a few times, unplugging things and re-plugging, no luck. I then removed everything and did the paper clip test, the PSU comes on, its fan spins, no problem. So I don't think it's faulty? It has a 2021 date on the box.
For now, I've removed it and put the AX860i PSU back in and now unRAID is up and running. Still have a Red X on Disk 3, but I'd like to sort out this power issue before running another parity sync.
Thanks for any help.