Hi All, I had almost the same problem with my iPhone 4. After water damage I couldn't make calls, WI-FI worked OK, but I first get only 2 bars in signal icon and after that all bars shows up but I still couldn't make any calls. Call screen frizzes when I try to hang up (no voice on the speaker too). When someone try to call me it give him ring signal but my iPhone didn't show anything. When I try to call someone his phone rings but he couldn't hear me (neither do I). I solve the problem using contact spray (DRY OIL-FREE CLEANING SPRAY; PRF 6-68) on the antenna screw and antenna connector and also on the "blue signal coil". I let it dries and assembly my phone. After this operation everything works fine. THANK YOU for your help Simon and Craig !!! I hope this will help anyone who has similar problems.