Hi everybody.
After installing the new version of Ubuntu, Jaunty or 9.04, the secondary jack for headphones stop working. The solution is quit simple.
- Open a terminal Application --> Accessories --> Terminal
- Type alsamixer
- Using the left and right arrows move through Master, PCM, Sound and Surround giving them volume (in case they don't have) with the up arrow.
- If any of them got the letters MM written in the lower part, then change it by pressing the m key.
That's what I did and worked.
Enjoy!