Nokia 3120 No ringer | Nokia 3100 ringer problem

For nokia 3100/20 ringer problem :
1. Check and clean pin board connector
2. Check and clean buzzer connector
3. Replace buzzer if needed
4. If the problem not solved, resolder/rehot buzzer IC, replace buzzer IC if needed
5. If the problem not solved, check UEM (Universal Energy Management) , replace if needed
6. If the problem not solved probably circuit broken, swap engine module

Nokia 3100, 3120, 6100 buzzer