My iPhone 4 microphone doesn't work when placing and receiving calls. It works fine on all of the other apps and I really don't want to buy a replacement iPhone from apple. I've tried most of the solutions to the problem except the ones that require taking your iPhone apart. Please help me!
I Had the same problem, can hear the dial tone when ringing somebody and I can't hear them either unless I put the speakerphone on, i managed to fix this by opening the iPhone ( mine is iPhone 5), and I found a loose screw at the top of the phone near the camera, tightened it and now it works fine. Hope this helps.