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Noisy coloured pixels on my Fairphone 2

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Tags: #<Tag:0x00007f9ff8f898b0>

#122

Hi folks,

Since Tuesday I’m having the same Problem with my phone.
So far all my attempts to fix the problem were without success :frowning:
Here is what I’ve tried:

  • I Got in touch with support - they think it must be the Core Module and it should be replaced. A new display module would stop working as well after about one month. As warranty is expired I would have to pay about 380€ for the repair.
  • I tried Cleaning the display connector
  • I disassembled the phone into its modules and wiped all connectors with a dry cotton tissue - this helped for a few minutes
  • I used contact spray (different brand than @letrollpoilu) - this also helped for a little wile
  • I inserting multiple layers of insulating tape on the metal framing on the opposite site of the PCB to create some pressure onto the contacts. This seems to work a little but I noticed that too much pressure starts to bend the connector. So at the moment I am trying to find out the right amount of layers. But this is a very slow process as I need to unscrew all modules and reassemble the phone for every try. So I would be curious how you used the cardboard @letrollpoilu ?
  • One more thing I want to give a try: Test with a new display module. @Stefan is so kind to offer me this possibility this week.

Well, now I will give the tape a new try …
Greetings, Alex


#123

Well, if a new core module should indeed be necessary, you can save a few Euros here (at currently 339,90 EUR + 14,90 EUR shipping to the EU and the rest of Europe) …


#124

Thank you for this link! I didn’t know spare parts are sold at other places than the Fairphone store.
I don’t think I will pay that much for repairing an old phone but invest the money into a new phone with more recent hardware. Maybe a Shift Phone (or something unfair)…

For my experiments with the insolating tape and cardboard:
I didn’t have any real success so far. It seems to be important that the pressure is applied very equally. It only takes one pin with bad contact to scramble the signal.
Does anybody know how these spring loaded pogo pins work? Do they need to be pressed a certain down a certain distance to create contact?


#125

I’ve used the same “Kontaktreiniger” to fix display connector problems and it has also helped a lot.


#126

@ElKrasso doesn’t recommend contact spray:


#127

Today I met with @Stefan and we tried with swapping screens etc.
We didn’t got the screen working, but we are convinced that the problem is not the screen itself.
It must be the connector.

The weird thing is that sometimes when pressure is applied behind the connector the screen works.
I did a little research about pogo pins. They are actually made to compensate uneven surfaces and vibrations. So it shouldn’t be the distance between the screen and the core module.
So my guess is: the problem is inside of the housing of the pins.

This is why I propbly made a big mistake this evening:

I can confirm this.
Back home I tried again with some spray (maybe too much) and it just made things worse! Nothing worked anymore. I had some success with blowing out the liquid with compressed air, but still the screen is not behaving well.

I don’t know if there is anything to fix these pins?


#128

I can confirm that the Problem is not the screen. I was thinking it was and openend a request. But yesterday I received a new screen and the problems stayed ecxactly the same…


#129

Jep. My screen was working perfectly with @Stefan’s phone and his screen didn’t work with my phone.

This will be the reason why Fairphone Support replaces the Core Module in this case.

Yesterday night I had a look at the pins of the back USB connector. They are just standing and soldered onto the PCB. The black surrounding is just kind of a frame. (I can take a picture later this day if someone is interested). The display connector is not that easy to take apart, so I won’t do that.
So there is nothing going on in the black part.
The solder points of the pins shouldn’t be a problem as they are quite sturdy.
It rests the contacting inside the pins (they are basically a spring loaded pin inside of a tiny pipe) - no idea how to fix this.
Or it is the PCP: one or more of the conductive pathes might be broken. This would explain the strange behaviour of the screen workingwhen the PCB is bent…

The only thing that worked for me so far was cleaning all contacts with a dry cotton fabric. But not for long either… :confused:


#130

Edit by @moderators: :warning: This post contains instructions that can cause severe harm to you. :warning:

So welcome in the club of broken pogo pins :wink:
I am lucky that I only have trouble with these pins at work.

There is one thing you could try before you swap your core module.
It is a dangerous action, but if you do not have anything to loose it is worth a try.
I guess you have (a) broken solder joint(s) on the pogo pin(s). Resoldering by hand would be hard, moreover most people do not have access to professional soldering equipment. But you do have an oven in your kitchen I guess.
So the melting point of solder tin is around 200°C, so you could try a self soldering session.
Dissemble anything you could from your core module. Heat up you oven to 220°C and put the core module with the pins up (!) in the oven for ~10 minutes. (! = You do not want the pins to get lost by the gravity if you put your module with the pins down, smaller parts, like resistors will be hold by the surface tension of the tin).
To check if the solder melted in the process time, you can use a pen on an empty solder joint before you put it in the oven. When it was melted the marking should be gone. If it is still there leave it for some more minutes in the oven.

Caution:
When the core module is hot and you take it out of the oven, beware shocks to the module. the solder is liquid and the parts are swimming on the liquid solder. If it will fell down it will be unusable due to the parts are shifted. Then you successfully made a Fairphone to a Shiftphone :grin:

I know it is a little nerdy to “cook” your phone to function, but there are some circumstances where that helps.
You could try a google search for more feed.

Edit by @moderators: :warning: This post contains instructions that can cause severe harm to you. :warning:


#131

Thank you! :laughing:

Can this be verified before? I mean there is some strange behavior I can’t explain myself: half an hour ago I reassembled my FP2 and turned it on and left it on the table. Everything worked fine, FP-Logo, Boot-Animation, Android Wallpaper - and suddenly the image went weird and nothing worked any more. So the screen went from perfectly working to the weird behavior without any external physical influence.

I’ve got a soldering iron. Would it work to heat up the pins one by one?

There are quite a few parts made of plastic on the board and I am not sure if they were applied after the soldering in the factory (e.g. the black frames for the pogo pins). For sure the thermal pad was applied afterwards.

the pins of the USB connector will be face down - but who needs those :wink:

I was thinking of getting one, didn’t know this is how they are made :grin:

But sounds interesting. I already thought of resoldering but not this way.
I might give it a try next month.


#132

What about the heat every electronic produces when in use. Thermal problems are the worst kind of problems you can get. As the device gets hot there are different expansions in different materials. Broken solder joins are often based on this behavior.

Is it made for SMT parts? Do you have a solder tip that small?

They can be fixed with heat resistant tape. You can get it in most hardware stores.

:wink:

The usual way to solder SMT devices is an hot air oven.

where this happens:

You could do it also by hand, but you need to be very skilled to do so:


#133

I did think of this as a possibility but did not consider the thermal expansion to be that strong.

Actually no, its a bigger one but I could get myself a smaller tip.
The pins are not that small anyway.
But I think it would be necessary to keep the black plastic framing on to ensure they dont shift away when the solder tin turns liquid as I can’t see if the pins are just standing on the solder point or if they are inserted in a hole for positioning.
So I thought of heating up the pins with the frame still in place.
But this plastic frame needs to be tested for its heat resistance. :wink:

BTW: This is what the Pins of the USB-connector on the back look like:


#134

I decided not to throw the PCB into the oven (yet).
I am selling the working parts of the phone, but I’m looking for a way to securely erase all data from the internal memory. Encryption wasn’t working any more.
Is flashing the operating system enough? I guess not…


#135

I think it can be done, but the thing is probably pretty technical.

You can flash TWRP, boot it, and dd if=/dev/random of=<path to mapped userdata partition> through adb shell. Don’t forget to mkfs.ext4 <path to mapped userdata partition> after that, so the new owner could use it fine.

Alternatively, you can do that on a file instead of TWRP (if you have ~60 GB sparse on you computer), and later convert it to a sparse image with Android SDK’s img2simg and flash it with fastboot. Something like (pseudo-code):

$ PARTITION_SIZE=`fastboot get-size userdata` # I don't really recall this subcommand
$ dd if=/dev/random of=random.img count=$PARTITION_SIZE
$ img2simg random.img random.sparse.img
$ fastboot flash userdata random.sparse.img

(Then you should create another img file, empty this time, mount it in the loop device, mkfs.ext4, img2simg and flash it with fastboot.)

The TWRP/on-device option is more straightforward, though.

Disclaimer: this is all experimental and I can’t really offer any guarantee. But I really think it is doable. I did some dding on-device to wipe the encryption headers (as explained on another post here in the forum) and flashed some custom sparse images when I tinkered with self-built FP Open and porting CyanogenMod.


#136

Hey axcro,

Here is how I’m managing the pressure of the connector. Simply some paper taped between the protection and the core module.

Untitled

Thanks a lot for keeping us up to date with your other experiments. My solution works like 70% of the time. When it’s not working I’m simply pressing hard with my hand trying to keep calm and then it works for a while… I think all in all it improves my patience skills a bit.


#137

Hi @Roboe,
I didn’t get it done with fastboot but with adb. (Actually I didn’t take the time to figure out the missing parts of your pseudo code :wink: )
Here is what I did:

  1. fastboot erase - some people say this is enough to securly wipe your data, but I have my doubt about this.
    fastboot erase modemst1
    fastboot erase modemst2
    fastboot erase cache
    fastboot erase userdata

    Link: https://android.stackexchange.com/questions/161103/what-fastboot-erase-actually-does

  2. flash Fairphone Sibon (actually this seems to perform a fastboot erase as well)

  3. I had luck that the screen was working for a few minutes so I could grant access for adb. The OS was asking me directly at the first bootup assistant, no need to go to settings.
    In adb shell I then performed the following command until no space was left:
    dd if=/dev/urandom of=/sdcard/junkfile
    This took several hours.
    Link: https://zackeryfretty.com/secure-erasing-android-devices-guide-for-the-super-paranoid-seller/
    (adb shell with TWRP didn’t work at first but since the authorisation from the OS it does, don’t know if it was my error or if I didn’t accept something due to the not working screen.)

  4. Removed the dummy/junk file(s)

I would say this is secure enough for me :smile:
The phone parts are already for sale…

@letrollpoilu: Thank you, but unfortunately this doesn’t work for me :frowning:

For my “other experiments”: I decided not to throw the PCB into the oven at all. I tried to heat up every individual pin for ~4 sec with the soldering iron (not sure which temperature my iron gets), but without any change to the phone’s behavior.

Overall I would say this problem only gets worse once it started to occur. I would advice everybody who starts to have these or similar issues to quickly backup all data and prepare an other phone for rescue.

Taking preparations for data backup and for wiping the phone is anyway a good idea for everyone :wink:

For me the Fairphone Journey has ended here. To bad it was no happy end …


#138

Hello everybody,

I have had the same issue here, for the last 2 months. First few glitches that were solved by restarting the phone (did not feel so different from the classic random reboot issue…)
It got worse quickly, and for me it has become obvious it was linked to heat. As the phone is prone to overheating, I am now convinced one chip got damaged with false contacts somewhere. Twisting the phone sometimes makes the screen working, but nothing permanent.
I feel that only replacing the core module would (maybe) work, but I don’t think it is worth it anymore on this phone : I would have loved to keep using it for several years, as everybody here, but a brand new recent phone is much cheaper, and my FP2 lost a bit of my trust after 3 years sometimes painfully owning it…

Just giving my feedback on the glitch, no real solution to share, sorry to say…

Cheers!

EDIT : applied the workaround from letrollpoilu, placing a filler between the case and the phone to put pressure on the pogo pins connecting the screen. Worked for some days, but now it is back to before, or even worse (I guess it forced on the pins that got broken further…).
In contact with the helpdesk, the solution is to change the full core module, so to expensive for me.
So I am out, buying another phone, see you for FP3 maybe!


#139

Hi there.
Same here. Tried a lot. Guarantee expired. Fairphone only offers replacement of the core module for about 380€. Frustrating.
It now seems obvious that the connector pins of the core module and the contact area of the display cannot …well, connect properly (Pressing the index finger pretty hard next to the battery helps).
So either the pins should stand out more (springs inside worn out?) or the plastic parts, keeping up the pressure inside the phone, are worn out. Either way this seems to be something so simple and mechanical that there must be another solution except swapping the whole core module?
Well. I hope somebody has an idea and I will continue following this thread. With some other second-hand-non-fair-phone…


#140

Hey everyone,

I have the same problems after a few weeks. Sometimes I can’t turn my mobile on, sometimes the screen stays black, sometimmes it works well, sometimes the screen starts to shake… I live in Bochum, Germany. Is here anyone near Bochum or Wuppertal, who has an FP2, so I could check if it’s a problem with the screen. If not I will send it to Fairphone I think. I tried to change the shell and do clean the contacts but nothing works. Do you have any idea? It’s nearly impossible to “work” with this phone, because you can’t be sure, if it works and for how much time.
Thanks in advance!


Display problem - whole screen filled with noisy pixels of different colors
#141

I moved your post here as you are talking about the FP2 and the other topic was about the FP1.