I have just successfully repaired my microphone. I had a strong noise or nothing came into the microphone.
I did the following:
I put a small chip of wood (toothpick) to the right of the USB plug between the display and the botton module.
And it works!!
I think for on speakers mode is a different microphone used. Check which microphone is not working in the settings-> system, maintenance -> check up-hardware diagnostics. (Hope I translated the steps correctly)
Sounds like your primary microphone is the problem. I recently had the same issue and I took out the bottom module and cleaned everything with a vacuum cleaner. Now it is working again.
UPDATE:
The problems came back. It probably was the taking the module out and putting it back in that helped more than the cleaning. 
I can sometimes ‘fix’ it for some time, by just pressing the bottom of the phone tightly together. Then the mic works.
It’s correct, it was the primary microphone. But my “repairment” worked only for a few days. So I replaced the bottem modul (it is my third one) again and I had success.
The next time I will try your cleaning, Thanks.
This should be made correct answer. Fixed it for me, I used tiny bit of paper folded multiple times where this guy put the little bit of tooth pick
Cheers mate, worked for me too 
This is a long topic with a very unspecific title. Lots of people with different issues post here. One solution won’t apply to all of them.
But I’m glad this worked for you. 
I’ve had this problem for yonks now, I even bought a new microphone about 18 months ago and it didn’t help. As I don’t talk much on the phone I’ve mainly used the secondary mic with the speaker on or earplugs (which is a bit of a nuisance as I wear hearing aids). Now I searched for trouble shootings again as I have several other issues with my phone and found this tip about bending the plug and it worked!!! Wish I’d found this earlier!
OK, I rejoiced too early! I noticed I hadn’t closed the blue buttons inside and when I tried again turns out I have to keep pressing the plug upwards, it’s only then the mic works. …
The primary microphone of one of my two FP2s stopped working today, produced a continuous crackling and hiss instead of voice. It was tested with the checkup tool. I cleaned the module and the main board contacts, to no avail. Here is the solution that I found: open the module by unscrewing the two Torx screws and by slightly lifting the side lock tabs. Inside you will find a pair of springs and golden pads for the vibrating motor and another pair for the mike. I cleaned the springs and pads and raised the springs for better contact. Reassembled and reinstalled the module, et voilà, problem solved, it’s working again. 
Sorry to report that this didn’t really solve the problem. Those pairs of springs that I mentioned are for the vibrator and loudspeaker. I checked again the circuit and unfortunately the problem is with microphone soldered terminals that failed and are impossible to fix. As you can see in the picture below, the microphone (little detached metal rectangle with four terminals) is a miniature piece with soldered terminals that are impossible to reach for resoldering. This is the major design flaw of the FP2 in my opinion: the mike is soldered way too close to the USB connector on a flexiboard. The mechanical stress caused by connecting and disconnecting the USB will inevitably lead to terminal solder failure under the tiny microphone. Conclusion: had to order a new bottom module.
Not that it makes the design any better, but at least this mechanical stress can easily be avoided for most use cases …
https://forum.fairphone.com/search?q=magnetic%20usb%20adapters
No mechanical stress at least for charging and USB connections to a computer.
USB OTG devices tend to not work this way, though.
Thanks for the useful tip, yes, this could have saved two modules during the last 3 years.
Look at this old post from mietze. It solved my problem by using a little piece of rubbertape:
Great! Mietze is a genius! Thank you! The test worked immediately!
@Reri_Haufler @Fairfish Where exactly did you put he rubbertape? i tried, but it didn`t work, but i think i might have put the tape at the wrong place. If i press the phone where the microphone is located it works (not so well, but because of that I am sure it es a connection problem).
Hi Miri,
i put it to the place where the screwdriver-tip is pointing to on the first pic. It worked for a couple of weeks, then the mic-module lost contact again, probably due to squeezing down of the rubber-material, which was quite ductile. I replaced it now, using a little piece of an old bicycle inner tube (picture 2), which should be quite non-deformable. After fixing the screws tightly, mic was working again. I hope, it will last longer this time.
Good luck
Fairfish
Additional Information from 9th June 2020: Mic ist still working.
I really need to remember this if I get mic trouble again! So I’m writing here more as a note that I can find posts I’ve commented in in my history… 
This forum has a bookmark feature . You’ll find the bookmark icon below any post (perhaps you will have to expand the icons there using the three dot icon first). Then you can easily see your bookmarked posts in your account.
Thanks! I just did the same thing with ductape.
OT: On the one hand, I am amazed that I can fix my phone with just a bit of tape. On the other, I wonder if I would run into this problem with a regular phone. Guess I will never know.
This topic was automatically closed 182 days after the last reply. New replies are no longer allowed.
