The Nokia X3-02 used a 5 pin digital microphone (DIGIMIC), and is mounted at the bottom of the PCB board. Refer to the solution below and do have check and replacement procedures on the highlighted components. .
Nokia X3-02 MIC Problem Solution
Before replacing the microphone, you may first check the DIGIMIC supply voltage across to a 100ohms resistor. The other two 100 ohms resistors which is also for the data and clock of the digital microphone.
So, check each of these resistors value, then replace if found already damaged.
If the supply voltage reading is okay, and the three resistors are also good, replacing the digital microphone will be the next option.