mic dont work after brake down to ck power btn sticking

Firstly, I'm assuming you mean the mouth piece mic, and not the noise cancelling mic connected to the audio jack flex assy. The mouth mic is connected to the dock connector assembly the plugs in about halfway up the logic board seen in steps 9-10 here dock connector. Check that connection and assembly for damage. Make sure its plugged in correctly, and that the mic is seated properly and lined up with the hole in the frame of the phone. It's either broken or torn somewhere, not plugged in properly, or not seated in a way that the sound is making it in. Good luck! The guide I linked to will have every necessary step to do what you need to do.