The solution below shows the microphone circuits including its voltage supply and audio data signal line paths from the Power and Audio IC through to the Digital microphone module.
Nokia 5220 Xpressmusic Mic Not Working Repair Solution
You may also check the voltage supply line paths, if the voltage is not present the microphone will not work.
If already tied installing a new replacement microphone and ensuring that the connection tracks were okay and also the three resistors were bot fine but the problem still exists, there is the possibility that the problem lies on the audio IC. Reworking it might possibly solve and fix the Nokia 5220 microphone problem.