Chosen Solution
I am having an issue where he mic for the Phone App is not working for calls. I believe that that is the bottom mic. To test, I have used the voice recorder and siri. Both work ok. Facetime audio and video both work as well. I recently replaced the Lighting connector ribbon, but it still did not help. It is only for voice calls that it is not working. Nothing is transmitted. not even muffled sounds.
Hello Nick. Was your bottom microphone the original problem, or did this problem only occur only after charging the charger port flex? It is very common to get a bottom flex that has defective microphone installed. It will happen once in a while from good suppliers. From a bad supplier, you could order 5 flexes and receive 3 with bad mics. The iPhone 6 really is not known for having any age-related failures on the motherboard which could cause this issue. However, the FPC Connector for the bottom Flex could have been damaged by mashing the flex down too hard while trying to get it aligned to plug in. Alternatively, you may have pried up a component next to the the FPC Connected on the motherboard side. In either case, the audio signal from the flex is not getting where it needs to go. These types of damage can really only be diagnosed if you have good magnification. If you have a local repair shop conveniently close by, stop in and ask them to look at your motherboard’s connector under a microscope. They would spot any damage pretty quickly. If getting to a repair shop is a hassle, order another replacement part (or two) and try your luck changing the flex again.
