HP desktop display shows for 2 seconds then shuts off

So I have an HP desktop display that comes on for about 2 seconds then seems to dim and lose its connection to the PC showing the display details in what looks to be minimal brightness then shuts down in about the same time frame

I tried many things (known-good cables, different PC, picture does show normally for a few seconds so I don’t think it’s the backlight, tried to change settings but it powers down before I can, etc.) and believe I narrowed it down to the power supply circuit board. I would like a second opinion but that’s what my diagnosis would be. Could anyone else give me some input as to what else I should try before having to change the whole board or the components on the board?