Odyssey X86J4105 won't boot

I have a Odyssey X86J4105, and I’m having trouble getting it to boot. Most of the time, pressing the power button does nothing. Once in a while, the power button lights up, but goes dark after around a second. Interestingly, the indicator lights on the ethernet port still light up. I’ve tried the power supply with different Odyssey units, so I know it works.

Any advice would be greatly appreciated!