T530: internal speakers not working

Hello there Ubuntu Forums,

I have a shiny new ThinkPad T530. For the most part it works, and Ubuntu 12.10 works really well on it. However, one of the problems is that I can't get the internal speakers to work.

Here's what I tried:

1. Restarting computer
2. Muting / unmuting sound
3. I tried alsamixer
4. I tried linux-alsa-driver-modules ppa, but it looks like that's for older kernels

Headphones do work fine. Internal mic also seems to work.

Any ideas?

Thanks so much for your time.