This is the Samsung B220 Mic repair tracks, a solution that may help fix a not working microphone.
Just refer to the higlighted components on the B220 PCB board and do a check up or replacement procedures.
SAMSUNG B220 MIC Jumper Ways
Repair Hints on Samsung B220 MIC Problem Solution:
1. Check and try to replace a new microphone.
2. Check the 2.4V microphone reference voltage.
3. Trace the negative and positive microphone connection line paths.
4. Check and replace the filter coils, resistors and capacitors.
5. Rework or replace the UCP300 IC.
