No sound in my headphones :-(

Hi, I'm using SUSE 8.2 w/ Alsa on a dell inspiron 8500. After switching from RH to SuSE I now got the strange problem that while my loudspeakers are working ok, I cannot get the PC to switch to using the headphones. If I plug the headphones in, no sound comes out of any speaker. I've tried fiddeling with alsamixer, but with no changes happening. Has anyone encountered this problem before and know how to solve it? Tarjei