SigmaTel STAC9750T Dead?

[j7n]

I recently received this motherboard: Intel D845GVAD2. It has STAC9750 audio codec onboard, but it's not working. The line out is dead silent, ADC works, computer behaves normally otherwise. If I play something back, there is a little crosstalk of this material onto the line-in recording. So, it doesn't look like a software problem to me, or does it?

The front_audio jumper block has the documented pins shorted except "Mic Bias <-> +5V". I didn't risk putting a jumper over those contacts, because if the markings are right, only the mic jack would be affected anyway.

What gives?