Hello, First off, does the front camera and/or proximity sensor work? those are also on the same cable at the ear piece. To test the proximity sensor would be to make a call and put your hand over the spot right above the ear piece. If the screen goes black then it works if it doesnt then there is something wrong with that cable. Another thing ive seen if is the phone thinks there are head phones plugged in it wont use the ear piece. That can be checked buy turning the volume up and down. When the pop up for the volume level comes itll say if head phones are plugged in or not. If it does then you would try cleaning the headphone jack, or you might have to replace that cable instead. The ear piece or headphone jack cable are very easy to do. Here is the guide to replace the earpiece... Замена разговорного динамика iPhone 5 Here is the guide to replace the headphone jack Замена коннектора Lightning и разъёма наушников iPhone 5 To answer you other questions, yes you could replace the board, but that is close...

Assuming you are talking about the ipod touch 5th gen then yes you can replace the battery without replacing the screen. Just pull the screen up, unscrew the metal plate and youll have access to the battery. The battery connections are covered by a black cover. just use a pair of tweezers to pull it off. Then just unsolder the battery and put a new one on! its really a lot easier than it sounds iPod Touch 5th Generation Teardown I linked iFixit's guide to the tear down. they tore the cable in the video because "we needed to pull off the soldered battery connections before we could tilt the logic board up to peek underneath." Since you don't need to get behind the board you wont need to worry about that. Again just take off the black cover, 3 solder points and youre all set to go!

could you use the mini 3 IC board on an mini 1/2 glass? take off the soldered home button from the 1/2 glass and just use the touch ID from the 3? Or maybe do the same thing without swapping the IC boards. just use the mini 1/2 glass and carry over the touch ID from the mini 3 onto the mini 1/2 screen? only reason i am asking is that the 1 and 2 used the same screen and the 2 and 3 are very close to being the same other than the touch ic and gold option. just seeing if maybe the screens could be just carried over.