I have had my Lenovo Thinkpad 410s for almost 2 years. Sound has worked flawlessly for Ubuntu 11.04, 11.10, 12.04. I installed Mint 13 this past summer and sound worked flawlessly. At some point I used the update feature. All of a sudden sound works for 3-5 minutes and then there is no sound on internal speakers. I do have sound when using a headset. I now have Mint 14 and I'm getting the same: Sound for 3-5 minutes and then speakers go dead. Interestingly, when I put laptop into hibernate (Fn+F12) and wake it up again, I get sound back but again only for a few minutes before it stops.
I have read as many posts as I can but none seem to address the issue clearly and with results that work.
Is there a timeout feature for sound?
Sound is affected system-wide without regard to what app is running.