Suddenly had this problem with my MX5021. There's sound coming from the woofer, but no sound coming from speakers. These connections seem fine. I've also reinstalled the audio drivers (Realtek).
At times happens to my set too I usually just turn it completely off(remove power cable) , and then remove the dock connector + satellite cables and replug them. It works .
Dont know what exactly causes the problem , I feel one of the cable gets loosen or something.