Microphone No Longer Working

Your phone has at least two microphones; one at the bottom of the phone that you use when on a phone call, and another at the top that's used for recording videos, switching to speakerphone, etc. If neither one works, that would tend to support the diagnosis of the repair shop that it could be something like a failed audio chip or something along those lines. However, if one or the other does function, I would lean toward it most likely being the microphone itself, although it could theoretically be a connector issue, but frankly those are rare - but then again, so is a failed audio chip.

Let us know if it's just one or both of the microphones that's not working and we'll see if we can figure out something that might help. Make or receive a phone call and try switching to speakerphone and see if the person on the other end of the line can hear you in either case.