No sound after drop

My iphone 3GS has no sound neither through the headphones and speaker nor through the earpiece. Furthermore it starts again every few mintues and random noise can be recognized through the earpiece. When I disconnect the ribbon cable 3, the iPhone stops restarting, but there is still no sound from the speaker and the headphones.

Does anyone has a hint, where the problem is? Thank you for your answers.

I was able to transfer the logic board of my 3GS into a proper 3GS housing, but the problem is still remaining. So I expect a hardware problem.

Does anyone has an idea where a possible shortcut may be located? My first idea was the FPC-connector of the ribbon cable 3, but everthing looks ok.