Dead FP3 - No charge, no LED, no boot

Hi everyone,

My FP3 (out of warranty) suddenly shut down a few days ago, with a battery half full. It kind of booted once for a few seconds, but now it shows no response whatsoever.
The LED does not light up when plugging the power adapter. I tested several adapters without success.

I disassembled the phone and reassembled it, no change. The bottom module has been changed a few months ago. I have little hope, I suspect a failure on the motherboard.

I just need your help figuring the voltage that I measured:

  • 3.85 V on the battery. Is that consistent with a batter level of around 50%?
  • when I plug the power adapter and remove the battery, I read only 1.6V on the pins showed on the picture attached. Shouldn’t I read 5V?

Thanks for your help,


Hi and welcome to the forum

I can’t be of much help right now but

  • 3.8V is fine fine for 50% of an old battery
  • The 1.6V ~ I will check tomorrow

All the best


I doubt that the phone will work without battery. This has been discussed on the forum before.
So what those pins output is likely not representative of the value with the battery connected. Also, 5V would be too much as a charging voltage for the battery. More likely somewhere around 4.2 - 4.4V max.
Or maybe I misunderstood. What exactly are you trying to determine with your measurement?

I was trying to see if there is the correct voltage applied to the battery while charging. But I don’t have access to the pins with the battery plugged in, so I tried without.
I guess you’re right, the behavior is different without the battery.

I think I will disassemble and clean all the contacts one last time, but after that it seems hopeless.

Just tested, and I have 1.65V

When there is no load there is only a test voltage.

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Thank you for the test! It seems normal then, the bottom module and battery don’t seem to have a problem.
I’ll keep you updated if I find something when I disassemble.

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If it does not turn on even though the battery has some charge, this possibly indicates a core module failure - especially if you can rule out the bottom module. :frowning:

There are several similar reports of sudden death

Just one example


Thank you to everyone for their insight.
As it looks like the Core Module is the cause, i’m not sure I’ll send it to repair . Considering the cost of repair, maybe I’ll buy a second hand one instead, so I’ll still have the spare parts from the current one.


If you don’t mind the cost of postage etc. you can have the phone tested by Fairphone and they will tell you the cost of repair.

If that seems unreasonable then you can have the phone returned at your expense and keep it as spares if you buy another FP3 etc.


Thanks for the tip, I think I’ll try that!

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few months ago I had something similar, the post of urs_lesse solved my problem (bad contact)

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Unfortunately I already dismounted and remounted the screen with no success. And the symptoms are different, the LED does not light up.
Thanks anyway for the advice.


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