Nokia N78 Ringer and Hands Free speaker No audio sounds solution
1. Check and ensure that the speaker is working okay, a saturated sound output is caused by a damaged speaker, replace it with a new one.
2. Clean the speaker terminal contact pads, make sure it is free from dust, corrosion and oxidation.
3. Check or replace the filter capacitors and filter coils.
4. For the right channel speaker not working, see to it that UI flex cable is not damaged, replace it as well if damaged. If the UI flex cable is okay, check both filter coils and capacitors.
5. If the both speakers,filter coils and capacitors is okay, try to rework the audio amplifier IC or replace if the problem still exists. Don't forget to rest assured that the line connection paths is well okay and not open or cut, check and trace it as well also. Good luck!