The solution below shows the connection line paths of Nokia E72 microphone circuit, which may useful for easy tracing and check up troubleshooting procedures. You may need to check the certain components that holds for microphone circuit and also trace its corresponding connection line paths for possible damaged.
Nokia E72 Mic, mouthpiece microphone problem solution
In Nokia E72 there are two 5-pin digital microphone module is being used for primary or normal mode, but you may find 4 digital microphone being mounted on the PCB board the others for handsfree mode, and other is noice cancellation. Replace all of them one by one.
The solution above shows the primary and secondary digital microphone which holds as a voice transceiver on the device. You may first check the corresponding connection line paths showed on the solution above before attempting to replace the two digital microphone assembly. Just be careful by removing the digital microphone module and ensure that the PCB solder terminal pads will not be damaged or lifted.