The Nokia 6700 classic digital microphone module is being mounted or connected to the keypad UI ( user interface) flex assembly. You may need to check the UI flex first for possible damaged and replace it, if found out. The solution below shows the connection line paths of the microphone on nokia 6700 classic. You may need to check this connection line paths too; Before replacing the microphone module.
Nokia 6700c Microphone ( MIC - Mouthpiece ) Problem solution - MIC ways