Hi guys, I've this problem that recently happened... My microphone does not work during calls, but it works when i try to record memo voice, skype, viber etc... AND i also noticed that when i hit the iphone hard on the back the microphone works again, shortly or the whole conversation, depends how i hit it... but when they can not hear me after I've talked to them and the microphone stopped working, i hit the phone again and will work again. Is there something i can do to make it work?? I'm out of warranty, so return it to Apple is not an option. I've looked for some threads that are similair and also some youtube clips and some of them tells that you can "fix" this problem by putting an cardboard piece next to a metal piece. Do you think it will work??