C500 headphone socket

[Guest selwin]

I rarley use headphones on my mobiles but I gave my C500 to my girlfriend and she found that when you plug the headphones in the sound doesnt fully cut off from the main speaker.

I have tried the headphones on my c550 and it works fine, I had tried them on the c500 when I first got it and it worked then.. it has been dropped once but I cant see how that has damaged it internaly?

Is there a known fault with the c500 or any ideas on how to fix?