This solution can be used to fix Nokia C1-01 Mic or mouthpiece microphone if it has no voice sound can be heard on the other device when a call is made.
The layout solution below which will show you where and what particular components that needs to be check and or replace if the microphone problem occurred on Nokia C1.
Nokia C1-01 Mic failure repair solution
The microphone module is being mounted on Nokia C1 PCB board and there are filter coils and resistors connected to it.