[SOLVED] 3 days using new PSU, system wont't post, hangs on GPU

[ppduckey]

Three days after installing and successfully using a new Seasonic GX650 PSU, my system will not post, hanging on my RX580 video card. At startup, the video card's fans spin and the blue power light is illuminated, but my Z390 Aorus Pro MB hangs with the VGA LED lit. My I5-9400F CPU has no onboard graphics, so I swapped out the RX580 with an old 9500GT that draws power from the MB. It works.

I reseated, relocated, swapped all the PCI-E cables between the PSU and the RX580 card. I reseated the card and tried moving slots in the MB. I tried shifting the card's bios switch. I uninstalled GPU software/drivers. No effect.

I don't have a spare PSU with PCI-E support, nor a spare video card that draws 6+2 power from the PSU.

I bought the Seasonic PSU after my original Cooler Master MWE650 started to fail under load (after only 10 months) and I have been ghosted by the Cooler Master USA support staff in the warranty replacement process. The Cooler Master PSU would cause shut downs with both the RX580 and the 9500GT.

The system was listed as a new, custom build on ebay about a year ago. The video card did not come with documentation and had some corrosion on its fins, which made me think the seller was miner who was cashing out. Since the system worked and the price was low, I didn't complain.

Is the fault more likely the PSU or the video card? Should I create a support ticket with Seasonic?

CPU: Intel Core i5-9400F
GPU: RX-580P42 VA.2 4GB
SSD: Samsung 970 Evo NVMe PCIe M.2 500GB
RAM: Corsair Vengeance LPX DDR4 2666 C16 2x8GB
MBD: Gigabyte Z390 AORUS PRO WIFI
Windows 10

 

[Flayed]

If the VGA light on the motherboard is lit and the system works fine with a different VGA card and you have a new high quality PSU it all points towards the RX580 being at fault. Given that you said it came from Ebay and looked used when you bought it, that it has failed seems the most likely explanation.