Voice does not register for anything except video recording

On the motherboard I'm working on no sound input works: not call voice, speaker phone, Google voice search feature, or sound recorder EXCEPT the video recording and it recorded my voice: no other method of recording works.. I'm told and read in here in another post that the bottom mic is responsible for everything except video recording. Since that worked, is it the bottom mic or something else? Blue Tooth doesn't work (voice) as far as I can tell and wired headset doesn't either... if I replace the mic is that probably not going to do it or is it a chip that controls that microphone separate from the top one? Note that water damage was reported although I don't see any signs of it and everything else seems to work fine.