Chosen Solution
I have just replaced the screen on my iPhone 7 and everything seemed to work on it eg - the front camera and 3D touch. However when testing sound there was nothing out of either of the speakers (the bottom speaker or the earpiece speaker) and when i got to click the volume up button nothing happens on screen. I can’t even adjust sound in CC and when i go to adjust the slider it doesn’t move. Any help would be greatly appriciated. Update (01/24/2019) UPDATE: I have recently solved the issue. Just to recap I replaced the screen on my iPhone 7 and after replacing the Boot times of the phone was upward of 5 minutes and there was no sound whatsoever from the device. This was all linked to a bad front camera / earpiece cable. I removed the cable from my damaged screen and transferred it into the replacement screen and Voila! The phone booted in seconds and the sound was back and working with no issues.
The front facing camera flex cable also has contact points for the ear speaker. This is a hard component for first time device repairers to remove. With that said, it’s really easy to break flex cables on iPhones. A little advice in the future is to use a little heat to loosen the adhesive then carefully remove the component.
