Xbox360 E Slim not power on

[Handbrake]

Hi,

Last week I bought a cheap XBOX 360 E slim which is RGH. My problem is that the machine doesn't turn on. The power supply lights up in green and nothing happens when you press the power button. I disassembled the machine and compare with my own running machine. I see the problem in that where there should be 3.3 V there is no voltage on the front panel, where 6 V is 9.1 V. Where do I go on the motherboard and where do I look for what needs to be fixed?

THANKS

Sorry for my poor english