iPhone 3G internal microphone not working

[omni-impotent]

A few months ago the silent mode of my iPhone 3G was switching on and off by itself constantly which made it unuseable. So I opened up my iPhone (I was following guides from the net but I still did it more violently that I would have liked), blew away some dust, remade the switch connections and that seemed to fix it. However, as a result of this the vibration mode did not work. I lived without this for a few months but then decided yesterday I was going to open up again to try to fix it.

I did not manage to fix it but when I closed up the iPhone the internal microphone doesn't work now! When I was accessing the vibration module with a metallic screw driver (bad idea! I know!) I created a spark very close to it (see photo).

Is this where the microphone circuitry is? Everything else seems to be working fine. If not, I may have just damaged the microphone unknowingly. I am happy to replace this myself but don't want to go through the trouble if I knew the spark/shorting that I did broke the phone....