iPhone 7 plus SOUND Problem

iPhone 7 Plus with sound problem. Today we have an Apple device that takes a long time to start and has an audio problem. To repair this iPhone 7 Plus, we have to lift the IC U3500, repair a C12 track, rebole the U3500 and resurface it.
It's a pretty complicated repair, because underneath this integrated circuit is the microprocessor, so we have to be very careful when we are welding and desoldering.
This failure, occurs little bit, at first you run out of sound, you can not record voice notes and in the end the phone will have problems starting or stays in the block.