If encountered and tried to fix this problem you may start to check the speaker, replace if it is already damaged, cleaned up the PCB board contact pads for the speaker terminals.
If already been installing a new speaker or cleaned up the terminal contact pads but still there is no ringtone or an MP3 music sound can be heard on it when being played.
This simple solution shows the left and right ringer (IHF)hands free speaker components circuit on nokia 3710 fold PCB board, that needs to check for further troubleshooting.
Nokia 3710 fold Left and Right IHF Ringer Speaker No Sounds Solution
Troubleshooting for the right speaker needs also to check flex cable first before checking the connected components on it. The left speaker's connected components are mounted and located near the bottom side of the PCB board.
Checking this components were a lot easier for these are composed of a filter coils and an ESD protection components. Just replace if found one of these components damaged to solved and fix Nokia 3710 fold Hands free and ringtone's speaker no sounds problem.