xbox shuts down after 15 min
 

Can anyone help me ?
The problem is that my xbox shuts down after playing for some 15 minutes.
I pull the mains , wait some, put the mains back then i won't have to use the powerbutton to power up , it does that by it's self.
It's an old version xbox.

Does your fan still work? Might be overheating if the fan crapped out.

xbox shut's down
 

No the fans are working.
I think it's a supply mather.
In some way the powerbutton does'nt work ,or work's all the time.

First I am going to ask if the modchip is enabled/disabled with the power of eject button.

If not, load up evox and let it sit for 15 minutes or whatever. Take a note of the temp.

It probably isn't a temp problem, though. You should check under the power supply. There are 2 points under the cord socket in which the solder cracks off and can cause a lot of problems. My xbox used to do that, I got a new power supply, and now it does it every 2 hours or so. If you have another xbox around, swap HDD's. If the problem stays, then it has to be the mobo.

It's a not modded xbox.
If the solder points are cracked , can it be fixed?

yah, you just have to resolder it. It should fix it, if that is the problem. Before you open the xbox, wiggle the socket up and down from the back. If it moves easily, it is probably creacked. You would also smell that "transformer" electric smell.

Checked the mains solder points, they are perfect.
Another thing is that i can't turn the power off with the power button.
It allways stays on untill it shut's off after 15 minutes.

When you press the power button, does it turn off "half way". Like, does the video go out and everything, but the power button and HDD continue to stay on.

I have to switch the power off ,pulling the mains plug.
To turn on the xbox , i have to plug the mains back.
The power switch doesn't react at all.
He feels allright and i don't think it's broken or something.
When i power on with the mains plug, everything works accept the power button

Well, i don't think there is too much you can do. With those symptons, it is probably either a malfunctioning eject/power board or the power supply. The only way to know for sure is by swaping them with another two and see if your xbox does the same thing.

This problem is unheard of to me :(

The switch is working perfect because I measured it .
It's a big problem because no one has heard about such matter.
Maybe it's a mobo thing.