iPod Touch Microphone stopped working after I replaced the cracked screen

I have repaired my children and their friends' iPod Touch 4th gen cracked screens. Seems like each kid cracks the screen 2-3 times per year. Anyway, on some of these, after the repair, the microphone is completely dead. I tried testing using the Voice Memo app that comes with the iTouch. I don't get any movement on the needle when talking into the mic or when tapping the back of the iPod Touch.

I have been able to plug an external microphone into the headphone jack, and that works fine. Unfortunately, the internal mic just doesn't work at all.

Is there something I could have done to break the internal mic? I have tried using a pin to clean out dust from the microphone hole, but that hasn't worked, and while doing it, there isn't even a bump on the microphone level needle in the Voice Memo app.

Has anybody had this problem before? There don't appear to be any plugs that could come lose with the microphone, but I could easily be mistaken. Any help or guidance or tips for repair would be greatly appreciated.

The best I can offer is to take a look at the detailed instructions for repairing the iPod Touch at iFixit: The free repair manual. Maybe you can locate something that will give you a clue as to why the mike isn't working.

Sounds like you tore the mic cable for the internal mic when you take the device apart. Or it isn't connected. I know it's common to tear them when you take the iPod touches apart.