No 3G after Front Panel Assembly replacement.

This is the 5th iPhone 4 that I have done. Never had a problem til now. After replacing the display panel I get intermittent reception. 1 bar at the most.

I don't know if this has anything to do with it, but durring reassembly, I tightened a screw a little too hard and broke off the tiny piece of metal that fastened it to on the Logic Board. See: Step #14. (The 1.4 mm screw circled in yellow)

Also, can someone tell me where all the metal to metal contacts are that I need to clean with windex?

Thanks,

Steve