If ever encountered this problem you may need to check and replace the IHF speaker if found damaged.
If the IHF speaker seems okay but still no sounds output, you may then proceed to check certain components which holds the IHF speaker audio signal.
Nokia C6 Ringer, Hands Free IHF Speaker No Sound Solutiontracing.
The IHF audio signals is feeds from the audio IC (AVILMA) and then filtered by filter coils before it goes through to the IHF speaker.
Tips for Repairing Nokia C6 Ringer IHF speaker:
a) Check the IHF speaker or try to install a new replacement spare parts.
b) Check the speaker terminal and contact pads and ensure that it is clean.
c) Check the filter coils and ESD protection resistors and then replace if found damaged.
d) Rework the audio IC if all of the above is been done but the problem still exists, this may possibly fix Nokia C6 Ringer Speaker no sound problem