FP2 microphone repair (work in progress)

Cool! Hope it lasts. I’ve tested two so far, the first one stopped working properly and the second still works right now. I’ve ordered some of those tiny leaf springs so I’ll test those right when I get them and report back here. I’m hoping I can get to a stable, reliable fix.

3 Likes

Just to link another post reg soldering broken mic, in case it somehow helps (I’m lost with all this, so apologies if you were aware or this actually the same repair)

4 Likes

Update: I received the leaf springs, they were a little too high but they were easily cut down to fit the available space. I soldered three into a module and it works perfectly - I’ll be testing it for the next week.

And if it keeps working, I hope to finally be able to start fixing modules on a larger scale.

9 Likes

Pretty cool. I just did my first teardown, and went a bit too strong on the two metal springs, which I sheered off with my guitar pick…
Wouldn’t it have been easier to take away the metal sheet instead of pulling off the PBC plate?
Well, now I have some more soldering to do…
Where did you get the leaf springs?

1 Like

Yeah now I’m thinking I can just remove the shield, clear out the sponges, make the holes in the plastic a bit bigger and then solder in the springs.

Contact is still not that reliable, though. Sound always comes through, but it often takes some tapping and flexing to get rid of background noise.

I think I can connect all three squares with some coated wrapping wire that I then connect to the shield (or some more convenient grounding point if there is one)… That way, all contacts are soldered, so you’re no longer relying on friction. It would still necessitate a full disassembly, but it would be a solid, reliable fix at last.

I got the springs from Otronic, they’re pretty cheap. They’re small but I still needed to carve out the holes in the plastic, and they’re too high so I had to cut off part of the springs to make them depress further. But like I said, this is still not a reliable fix. I’ll try out the wire idea tomorrow and report back.

1 Like

I soldered in a wire. It runs from square to square to square and then to one of the screw holes next to the big module connector - and it works! It still took a tap to the phone to get all the noise to go so it isn’t perfect, but that probably has more to do with the amount of experimentation this particular module has been subjected to.

I’ll be testing this mod for a week, again. Hope it keeps working, but I don’t foresee any way this could fail. No longer dependent on friction, not sensitive to deformation of the module.

Protip: cheapest way to get thin coated wire is to take apart an old appliance with a transformer, or an old transistor radio with a bunch of wire wrapped inside.

5 Likes

Woah, that’s great! I will do that! Can you post a picture so that is clearer to me? But I think I got it anyway. I’ll try that!

1 Like

So I tried today to solder the little springs I sheered off while detaching the PBC-module :neutral_face: and to solder also a wire as @robbert.f described. Well, it didn’t work for me. Hmm. Why that? Any ideas?
(I got the wire from an old telephone cable.)

I think that as long as you have those points all connected to each other and the wire connected to ground, it has to work unless something else broke. The mic is just barely surface mounted on there, I’ve knocked one loose before.

But here’s an enhanced picture of a revised setup.

Don’t mind the battle scars - this module has been through a lot of experimentation and to its credit, still works.

The wire goes from one spring to the pad, to the next pad, to the other spring, and then to the final pad.This wire is quite thin so I may try replacing it with something thicker but honestly it shouldn’t make a difference. Sounds great!

5 Likes

Oh, great! You give me new hope! Your module looks horrible, and it still works… I will get mine to work, too! :mechanical_arm: :man_factory_worker:
I am back to my soldering iron, too! :wink:

4 Likes

Hello robbert.f,
here is ale6 one more time, I wrote a time ago, in december. My english is not so good. But I wanted to ask you: can you repair the bottom module (microphone) from the FP2? Or do you have one? Mine is broken and fairphone does not send them anymore. I´m sad about this. It would be great to become an answer if there would be a possibility that can help me.
best regards

Not necessarily what you’re looking for, but did you consider this possibility?

1 Like

Hello Alex,
are you german? So we can write in german.
I´m waiting for an answer from fairphone for the possibility to send my FP2 to repair it but they didn´t answer yet. It is always during a lot of days…
I hope they will try to repair, I think it is what you mean?
best regards
alessandra

1 Like

Well, I solder tonight my module as you showed it, @robbert.f , with a thin wire. Actually, I think it’s pretty nicely solder! (Sorry, I can’t post pictures, since it is my only smartphone…). But still no signal input from the microphone, it’s like dead.
Anyone has any more ideas what to do??

1 Like

I don’t have any spares right now, I’ve given away all my working bottom modules except the repaired ones, which need re-repairing - hopefully I’ll get these things working soon and I’ll be able to fix more. At that point I’ll open a giveaway thread.

@BrFabian, you may have knocked loose the microphone module. It’s the tiny little can next to the USB port. It’s surface-mounted and it’s barely held on there, but I’ve managed to reflow two of them successfully.

The trick is to get your soldering iron, get some solder on it, and then hold the hot solder against the other side of the PCB, so right under the microphone. Like so (mic on the top, PCB in the middle, soldering iron with solder blob on the bottom):

Let it heat up for a minute or so to let the solder under the mic melt, remove soldering iron, let it cool down, see if it works.

3 Likes

@robbert.f thanks, I will check that!

@robbert.f so I am right now checking that. It seems to me that the mic is firmly in hold on the PBC. It doesn’t move when I try to push it a bit with a plastic rod or my finger nail. And I don’t see any soldering on the downside of the PBC module where the mic is placed (only where the USB is). So I don’t understand why putting solder underneath the mic should help… Perhaps we don’t have the same PCB module model? Mine is REV 3.2.
:thinking:

Hello robbert.f,

I have a second bottum module and the microphone is broken. I have tried out all other solutions (none of them fixed it), so the only possible cause can be that the contacts under the microphone are bad.

This was explained in some earlier posts. I copied some pictures from that post to show the problem again:

It is very fine work to solder these extremely-small contacts. For that reason, I have not been able to repair it.

But if I understand correctly, putting a soldering iron on the opposite side of the microphone module will produce enough heat to melt the solder in the microphone and allow them to make contact again?

1 Like

Precisely right. Doesn’t work all the time and I’ve so far encountered one module where the fix won’t last, but the three other ones I’ve fixed this way are still going strong.

2 Likes

Just an update if you are interested.

Heating up the backside of the module as you suggested didn’t work. So I took the microphone off and soldered the four contacts as suggested in another post. Although it is extremely small and delicate work, it is easier than I anticipated.

The hardest part I had was re-attaching the microphone! Heating up the old glue didn’t attach it well enough. So I had to re-glue it.

If you do not have conductive glue, it is a difficult thing. I re-glued it from the outside (e.g. along the side) so that no glue got between the contacts.

Long story short, I soldered the 4 contacts on the microphone itself and I also put some solder on the gold squares.

But the microphone still doesn’t work. So I have to write the entire module off as “defective”.

Maybe it is down to something simple, but after doing everything recommended here (which worked on another module) I am not willing to spend any more time trying to find the problem!

Just a quick question: When I take the modules apart, they never want to seem to go back together. It is easy to break the white clips at the bottom and the metal clips never all seem to properly “click” back into place. Did you have this problem too? What have you done to solve it?

Thanks.

2 Likes