xbox shuts down after 15 min

[Quall999]

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.