Chosen Solution
I have tried the elimination tactics that I can find but the symptoms don’t exactly match what’s suggested. My phone records sound normally in every situation except video from either camera. Siri, voice memos, phone calls, FaceTime all work but videos give no sound whatsoever. Even if you put in headphones and blast the sound there’s nothing. I’m perfectly confident cracking this bad boy open and fixing it but I don’t know which mic to replace! Please help and thank you in advance :).
There are 3 microphones in the iPhone. https://support.apple.com/en-us/HT203792 The bottom microphone is for Voice Memo and phone calls. The other microphones serve as error cancellationThe (top) front microphone is used for FaceTime calls, Siri and selfie videos with the front camera (FCAM). The top back microphone serves as error cancellationThe (top) back microphone is used for videos with the rear camera (RCAM). The top front microphone serves as error cancellation Make sure you update your device to the latest version of iOS and then try to isolate which microphone is not working properly by trying each individual microphone with the related apps above. I find it odd that you say both video modes do not record sound, perhaps it has something to do with noise cancellation not working. If the issue affects all the microphones, then it could be the Audio Codec IC on the logic board. Anything at the logic board level will require micro-soldering so you would need to find a repair shop that offers those services.
