No sound in my laptop speaker until I plug in my headphone

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http://askubuntu.com – I had this problem since I upgraded to Ubuntu 12.04. There is no sound coming from the laptops speakers. When I plug in my headphones in the Mic jack then the laptop speakers work. I already tried opening up alsamixer and putting Master to 100<>100. No dice. Card: HDA Intel Chip: SigmaTel STAC9200 (HowTos)