360s powers on then off red light on psu
So here is the story: I repair rrod xbox consoles so my friend thought he would buy a cheap 360s on ebay (warranty seal broken) that was broken and have me fix it. The problem is that when i try to power on the xbox it chimes, turns off, and the light on the brick is red. The power brick powers up the halo reach 360s that i own so the problem is not the psu. I have checked all of the usb ports to make sure nothing is shorting out. I have also taken the mobo out of the chassis and all the solder connections look fine. I was looking around the web and some people were reporting that this could be due to a bad mosfet. I was wondering if this was true and if it is how i would go about testing the mosfets figure out which one is bad. Also if any one has and other ideas feel free to share them.
Thanks and sorry for the long description,