Sudden restarts of Acer Aspire 6920 laptop?

Question

Iron

The laptop has two operating systems Windows 7 and Ubuntu. After updating Ubuntu to 11.10, sudden reboots began. (probably nothing more than a coincidence)
The symptoms are as follows: regardless of external reasons, the laptop suddenly turns off (as if you hold down the shutdown button) and starts loading after a second or two. This happens in both Windows and Ubuntu. And if you listen to music or watch videos in Ubuntu, then the reboot does not occur. (up to the fact that if you turn off the music, then after a short time there is a reboot, I manage while aplay / dev / urandom) In Windows, listening to music does not produce such an effect, i.e. When playing music, reboots also occur. Nevertheless, if you run a heavy game, then there are practically no reboots. (for example, many hours of gaming sessions in Skyrim occurred without interruptions for reboots, although once when reading books, a reboot occurred,
The temperature of the equipment does not go beyond reasonable limits (it was measured immediately after reboots), the memtest run passes without errors.
All of the above was done with the power cable connected, because. The battery is exhausted and does not hold more than half an hour of work. With the battery removed, reboots also occur. On one battery, reboots apparently do not occur. With a new battery and a different power supply, everything was exactly the same.
I would not particularly like to take the laptop to a service center. What can I try to restore the normal operation of the laptop and what could be the problem?

Answer 1

This laptop model fails NEC capacitor assembly. Replacement required.
More details in the video: https://www.youtube.com/watch?v=zt7rP-roZ5w
https://www.youtube.com/watch?v=CpysrfmDuOs

Answer 2

An arbitrary reboot can be caused by local overheating (the thermal interface dries up and when the case moves, the crystal instantly overheats in a small area) - it happened on the EEE PC 901 netbook - it is treated by opening and replacing the thermally conductive garbage (I put copper plates on thermally conductive glue).
Until the first time I cleaned the cooling system and smeared thermal paste, the system did not have time to report the cause of the fall, and after smearing thermal paste, it managed to say that critical overheating (although immediately after the reboot the temperature was normal).
It's like an option.

Answer 3

And try in the power saving settings, disable the option to "put hard drives to sleep when idle." It looks like at the moment when the hard goes to sleep your computer and reboots. Well, or drive a car with another hard drive.

Answer 4

Boot from any LiveCD, use the system, see what happens.

Answer 5

Freezing, obviously. Wrap it up in a towel!
In general, I’ve seen this a couple of times on desktops, I don’t know how to logically explain it, but changing the power supply always helped, maybe some track cracked on the laptop board ...

Answer 6

There may be bads on the screw. You probably have BSOD disabled in the BIOS, in any case there is a crash log in Windows. You can see the error there. Maybe something from the IO area