Dell optiplex 9010 AIO no POST issue.

Having an issue with a Dell optiplex 9010 AIO not performing its normal POST behavior. When I press the power the machine starts lights,fans kick on but no Dell log indicating POST. The computer will shut off after a few minutes and try to start again. I am not getting any amber lights or beeps the power comes on and the fans spin up their is no POST. I tried connecting an external display, unplugged all the devices, tried another PSU and RAM.

I believe that the issue is either the motherboard or the CPU and i'm leaning towards the motherboard.