Here tip for Nokia 6300, 3500, 3110c Handsfree problem | fault :
1. Upgrade firmware / software.
2. Clean Microphone connector, replace Microphone if needed.
3. If not solved check Handsfree jack / connector, replace Handsfree if needed.
4. if still not solved check or resolder asif emif, replace asif emif if needed.
4. if still not solved trace sound circuit .
