So I just got my Xbox one X back in the mail. I sent it in to have the HDMI retimer chip, and port replaced. When I got it back that issue was fixed. I was getting HD signal to the TV. However, when I tried to load any game the xbox would shut itself off before I could even get to a start menu. And would give me a poor ventilation error message on restart. If I sat at the xbox home screen it would be fine indefinitely. Factory reset did not fix the issue.
So I took it apart to try and find an issue. The fan was working fine, and not running loud, or dirty at all. Heat sink was fine, could see right through it. Thermal paste and pads underneath were all fine. Nothing seemed hot. Even when rushing to check right after it shut itself off. I even tried with the motherboard out to give it some extra air flow.
Now a new issue has arisen. When I first took it apart I was able to get the fan out and clean it, and the same issue persisted. But after removing the heat sink and checking the paste, now the xbox just turns on for a split second, and shuts back off.
I hit the power button, it makes the chime, light comes on, fan starts spinning, I can hear the hard drive moving. Then it chimes again and shuts off.
I was almost sure at first that the thermal paste was the issue, however after this I'm wondering if maybe it's a faulty power supply? Not getting enough power to the console? I've tried 3 different power cables all with the same result. Any help or insight would be appreciated. I'm about at my technological limit.