Chosen Solution
The ringer on my Galaxy S has no volume on incoming calls. This is an intermittent problem. I have reset the phone, turned up the volume to full. This also happens when I set ringtone.
1)dial #0# Check whether ringer is working or not 2)reset the device and try to update firmware if available 3)Check the impedance of ringer : it should be 8-32 ohms 4)if impedance is very higher than above mentioned you should have to replace ringer 3)if no 3 true you should check audio driving part of logic board
