nokia 6100 ringer problem

just wondering if any ideas just got hold of my nephews phone and it works perfectly except when you get call it just vibrates, but no sound but you can hear the caller. checked profile settings all ok. also changed parts of his phone with mine as we have the same ie keyboard+screen, chasis and green pcb. appears to be a prob on the pcb board. can anyone tell me is it a seperate ringer or does it come out of the speaker. as a website i use claims to have two seperate items available.

thanks
the ninja