How to Make Headphone Jack Work Again?

Howdy,

A little while ago I discovered the headphone jack on my MacBook does not output sound.

Let me describe what happens:

Sound comes out of the internal speakers fine.
The computer detects the headphones and mutes the speakers when I plug in the phones (per System Preferences -> Sound -> Output).
No red light from the headphone jack.
I know these phones are good; I've used them on other devices.
Audio is not muted w/ headphones in.

I've searched through the archives and have seen this problem described one or two other times, but no solutions offered.

Should I reset the PMU/PRAM/any of that stuff?

I'd appreciate any help here.

Thanks.

bp