Here's the solution for nokia 3720 classic hands free, ringer loud speaker problem repair. The solution shows the particular components may need to check after ensuring that the loud speaker is working and in good condition.
3720c Hands Free, Ringer loud speaker repair solution
If the loud is speaker is okay but there is no audio sound output can be heard when activating handsfree or ringtone, you may check and by then replace those pasricular components indicated on the solution picture. Those components is composed of a filter coils and ESD protection resistor. Check also the line tracks of each corresponding connection.