| Hi,
here there's many things to test:
- May be you have bad mic quality.
- Audio filtring is bad.
* passive filter such as some RLC bridge
* Active filter such as the audio IC and the proscessor.
So make a good flux and rehot all Audio circuit( be carefull to not heat the CPU very well elese your phone will go forever).
use service manual to test RLC filtring.
good luck |