i have iphone 3gs 3.1.3 and the mic is not working.

i took it apart to find the root of the problem and realized that if i apply some pressure to the point where the cable connected to the rest of the board(which holds speaker etc) the mic starts working.

how can i fix it.
can someone give me the link of a video or something helpful which will show me how to take mic apart or how to repair it.

please don't suggest me to buy a new mic or whole dock connecter set because i don't wanna spend any money on 3gs just because a lose mic connection.