FP2 dead - red light on constantly?

[NEast]

@Leo_TheCrafter

The standard procedure for this kind of issue is:
…

Leo, that is very helpful. Thank you for such a detailed reply. Do I take it, from your message, that this should really be the first step? Even before trying to identify exactly where the short is, or whether there is a dead IC? Unfortunately the shops I have contacted so far either say they don’t do phone PCBs or they don’t seem to do anything other than screen replacements!

Regarding eMMC recovery - I’m not keen as that is the end of the phone, but would be interested what you thought of this: eMMC data recovery from damaged smartphone | Dangerous Payload

@Patrick1

How clean is “clean water”? Do you mean distilled water or even ultra-pure water which often is used e.g. in semiconductor manufacturing processes?

Thank you Patrick. Yes, I knew that if I stopped to think about it. I guess I was just meaning that it wasn’t the sea. But indeed it was not the handy bowl of distilled water that I keep around Thanks for referencing the water articles - although I was half aware, I thought it was dry enough, and had urgency to use the phone - retrospect is always easier! Hopefully there will not be a next time, but you never know!

---

@Paule and @BertG

Thank you for your pointers. I had found the link you attached, but obviously hadn’t read it properly. I will investigate further tomorrow.

---

Thanks everyone for your help. I will try to remember to update the thread when I have an outcome - whatever that be.

(I felt really sad to see the aforementioned repair shop in Newcastle already had a Fairphone with “the same problem” and that the owner had left it with not much hope. It sounds like there are a lot of more able people here and around the world.)

[Leo_TheCrafter]

The eMMC data recovery can apparently be done with the right tool, but that would only recover data, not repair the device.
Cleaning with 99% ethanol should always be the first step.
Having to solder is not always neccessary, had an iPhone 6 that worked after just some cleaning.

[NEast]

@Leo_TheCrafter

would only recover data, not repair the device

Thanks Leo for the heads up. I do realise that it would be then end of the phone. I am only considering it as a last ditch attempt if the phone won’t work again.

@Leo_TheCrafter

Cleaning with 99% ethanol should always be the first step

I’m now trying to decide whether to send it in to a repair shop for this sort of thing or do it myself, accepting it may not work and a repair shop will then be necessary. Obviously I don’t have an ultrasonic cleaner, but otherwise is there much harm in trying with some ethanol (Isopropyl Alcohol) first, in your opinion.

Thanks for all your input - really appreciated.

[Leo_TheCrafter]

Really make sure that your solvent of choice is at least 99%, 80% is not acceptable and can ruin the device even more to the point that the demage is unrepairable

[NEast]

Thanks Leo. Appreciate you checking that I understood it must be the right strength.

The two options (if I do it myself) seem to be from RS Components (https://uk.rs-online.com/web/p/precision-cleaners-degreasers/2274427/) or CPC Farnell (https://cpc.farnell.com/electrolube/ipa01l/ipa-cleaning-solvent-1l/dp/SAIPA1L). Both are reputable electronics suppliers in the UK and the items seem to 99%+ IPA solvent.

I will probably give this a go as a £10 attempt to fix. I have found a shop that is not too far away that supposedly does water damage repairs, so that is my next option. Will let people know here if I have any joy, so that they can (or not) get more trade

[Leo_TheCrafter]

Yes, you can also use q-tips to brush over heavily corroded areas.
Protip: If you sharpen a tootpick to a very sharp point, it can be used like a tiny brush to get inbetween capacitors and other components

[NEast]

A little update…

I bought two IPA cleaners (one bottle, one aerosol) from RS Electronics.

• RS PRO 1 L Tin Isopropyl Alcohol (IPA) for PCBs (Stock No. 227-4427) £10.64 inc VAT
• Ambersil 400 ml Aerosol Isopropyl Alcohol (IPA) (Stock No. 780-5225) £11.09 inc VAT

I stripped down the phone to just the core module, removing the shields. For other users trying this, it is possible (with a very small screwdriver for example) to remove the shields on the front and back of the core module. They actually just clip on. You have to get between the large flat plate and the frame underneath. I will try to photograph it next time…! You do not have to peel the black graphite thermal sheet - (unlike the instructions in the iFixit tear down).

I bathed the main board in the IPA for a good hour, gently agitating it every so often. I then removed it with clean gloves and sprayed IPA from the aerosol into the various ICs, focussing on the PMIC. I dried the mainboard in the oven at 100 deg C for 30 minutes and then let it cool. I rebuilt the phone and it charged, and turned on.

That was Sunday. Yesterday (Monday) I managed to use it all evening (plugged in) and I got all the data off it. However there seemed to be a huge battery drain issue. I left it overnight doing nothing and this morning the unit is back to square one. Just a red light, no charging etc.

I will try recleaning it, but it may need an ultrasonic cleaner (I don’t have one) or more. If anyone has any good ideas then do let me know. At least part 1 of the mission is accomplished!

---

@Leo_TheCrafter - Would either of these cleaners be adequate for this sort of job? It is not something that I have ever needed before, so I can’t imagine using it a lot in the future, so don’t want to spend too much on a “hopeful” repair technique: https://www.amazon.co.uk/Ultrasonic-SKYMEN-Jewellery-Eyeglasses-Toothbrush/dp/B07H2DDM57 https://cpc.farnell.com/james-products/ultra-7000s/ultrasonic-cleaner-750ml/dp/SA03348 Is there anything I need to look for in a USS cleaner? I know that this isn’t heated, but then I can add warm water for the amount I’m doing.

[Leo_TheCrafter]

I wouldn’t reccomend buying an ultrasonic cleaner, If you have no other use.
Try cleaning with more IPA and use toothpicks and Qtips.
Try to shake the board in the IPA, so that the IPA gets under the ICs.
It is also common that waterdamaged phones have a wrecked battery.
Maybe a fairphone agle can lend you a known good battery.
I had a “waterproof” camera , which got wet with seawater, which destroyed the battery to the point that it wouldn’t even turn on. If the short was somewhere, like VCC_Main, Which is essentially, the battery (Terminology from IPhone, happens very commonly on them, but every phone got such a power rail, sometimes also known as SYS or Main, can be identified by it’s voltage range of 3.6-4.2V or it’s connection to the Charger/PMIC) could drain completely, destroing it.

[NEast]

An update (and a question - of course!)

*Edit - @Leo_TheCrafter has noted that it was probably an inductor, not capacitor, so I have updated the information here to reflect that!

As an (obvious to me) warning to others. A lot of what I have done is trial and error and internet gleaned / desperation. Please do not take this information as the “right way” to do things, but hopefully you can judge for yourself by me providing my experience.

I did end up buying an Ultrasonic cleaner (sorry @Leo_TheCrafter - I’d already ordered it by the time you responded because I had a particular time deadline). I have no idea whether it made any difference. I bought https://www.amazon.co.uk/gp/product/B07GWMPVXW after noting that an electronics specialist was selling the same machine with added branding. I also bought https://cpc.farnell.com/ambersil/6330001300/ultrasonic-cleaning-liquid-1ltr/dp/SA02601 and some de-ionised water from Halfords. I basically diluted the cleaner solution with deionised water and then “cleaned” the stripped down board for 30 minutes. I then rinsed the board with more de-ionised water, then a good wash and spray with IPA cleaner (as above) before drying in the oven at 100deg C for 30 minutes. Naturally letting it cool before touching and reinstalling the board.

No luck. Same red light. However, I then looked closely at the board, and my pre-cleaning pictures and noted that a capacitor / inductor had blown (it was blown before I cleaned it - I just hadn’t spotted it). The photo shows the crack in the ceramic and the residue leaked onto the PCB.

I bought a solder mop https://cpc.farnell.com/servisol/200004305-1-5mx1-5mm/soldamop-red-1-5mm-x-1-5m/dp/SASOLDAMOPSTD and tried to desolder the capacitor / inductor. I failed. I didn’t have the right tools or skills. I gently removed the cracked and failed capacitor / inductor by breaking it to pieces (not a lot of force was required). The solder joints remain, but the gap between them is as good as it being removed.

I have not replaced the capacitor / inductor. I recleaned the board as above and tried again.

Success! The phone now works and the battery drain issue has gone. Presumably this capacitor / inductor was causing a mild short circuit.

---

The only thing which isn’t working now, is the rear speaker. This worked after my initial success, but has obviously been damaged in the second attempt to get it to work. I have tried switching out the bottom and top modules with no success. The strange thing (to me) is that the headphone socket still works. So if I do checkup on rear speaker with headphones I can hear the Fairphone ringtone. The ear speaker and microphones both work. The audio module is therefore clearly still working. All the other bits of the bottom module are working (USB, vibration, microphone) - just not the speaker. If anyone has any suggestions where I could look for a fault I would be very grateful. @Leo_TheCrafter I note that you have just managed to design a new bottom module - are you able to point me in the direction of which pins are used to connect the speaker and where I should look for a pcb failure?

---

I’m going to put my pictures of disassembling the core module separately, since this post is already too long (now uploaded at Stripping down the Core Module). Any questions or hints gratefully received! The best thing is this message is being sent via my Fairphone

[Leo_TheCrafter]

I don’t think telling you the pins will give you any advatage. I only know the pins on the bottom module, not the circuit on the mainboard. I can’t say for sure, but it looks like you got rid of an inductor, not an capacitor.
Inductors are used to drive speakers, create voltages for the speaker amp and much more.
If you want, you can check the voltage at the component from a known good board.
Capacitors are usually brown, some black with a white stripe on them.
If you want, you can try checking the resistance between the two pads. If it was an inductor, it should be OL to a few kohm. There should not be a resistance to ground lower than maybe 100ohm check between ground by connecting one probe to one of the pads at a time and the other one to one of the remaining shields (SIM slot should work, too). If you have removed a capacitor there should be close to 0 ohm on one side and a few 100 to a few kohm on the other side.
If it turns out, you have accidently removed an inductor, it’s quite likely to be for the amp, to drive the speaker. The best solution would be to replace it with an inductor from a donor board, maybe check with the fairphone angels, or at you own risk, replace with a 1µH inductor of the right size. But please wait and write back before trying any of those methods, just meassure. I can give you tips on some more andvanced soldering operations.
A short rarely damages anything badly on a power ciruit (have shorted quite a few IPhones), but if sth happens, you have a paperweight, unless you can find out the exact ICs.

[NEast]

Leo - Thank you!

@Leo_TheCrafter

it looks like you got rid of an inductor, not an capacitor.

Ooops On the plus side the phone works now - except for the speaker. Could a shorted Inductor cause the phone to stop working? My basic understanding suggests they are supposed to conduct anyway, so I am surprised it could short circuit “more” and render the phone useless. But then I’m sure you see my electrical knowledge is limited

Interestingly, there was a long fine wire which seemed to be coiled within the component when i took it off the board. Sounds like an inductor? Sorry to sound so, um, dumb!

@Leo_TheCrafter

checking the resistance between the two pads

I assume that you mean on the board (rather than the two pads on the inductor? The component is rather fragmented, if I can even find the dust…!

@Leo_TheCrafter

But please wait and write back before trying any of those methods, just meassure.

Thanks again. I certainly will. I am appropriately rebuffed - I can see your eyes rolling! Things are less urgent now, so I can walk steadily to fix the final problem. I don’t think I have any fairphone angles anywhere near me (Newcastle upon Tyne, UK).

@Leo_TheCrafter

tips on some more andvanced soldering operations

Would be gratefully appreciated. Sadly every shop that I have approached has at best directed me elsewhere, but usually been completely useless. It would appear that society’s desire to dispose of and replace has become deeply ingrained at all levels.

Really appreciate all your help @Leo_TheCrafter - an amazing support to the community. Thanks.

[NEast]

For people like me, less familiar with electronic components, I found this a plain reading explanation:

http://www.differencebetween.net/technology/difference-between-capacitors-and-inductors/

[Leo_TheCrafter]

If an inductor is damaged, it might be a dead short, instead of a real inductor, causing the output voltage to be unregulated, the PMIC detects that and shuts down

[JeroenH]

@NEast

Success! The phone now works and the battery drain issue has gone. Presumably this capacitor / inductor was causing a mild short circuit.

I just wanted to say: kudos, and thank you for sharing your detailed journey. This whole thread has been an interesting read, especially as a Fairphone Angel. I don’t see myself doing such though.

[NEast]

Thanks @JeroenH - I’m glad that you have found it interesting. I was determined not to create another abandoned “my phone’s broken” thread

@JeroenH

I don’t see myself doing such though.

I think it is worth remembering I definitely did not set out on this route. It started with an accident! I turned to the professionals who all turned away. I had data that I wanted and a broken phone - there wasn’t a lot to lose. I have learned a lot, but would definitely recommend a professional doing the work if you can find one that you trust!

I think the biggest thing that I have learned, is that although we all know rice is bad for wet phones, drying them out isn’t much better. (Although a little over simplified): Turn it off, remove the battery and submerge it (no, not the whole phone!) in IPA as soon as you can. This will remove the water and electrolytes. Then dry it before turning it on. I don’t think this is mentioned in any water damage guide, but is now my understanding.

All the best Angel-ing.

[NEast]

Hi Leo,

Sorry for the (huge) delay in replying. Life has had some big turns since I was last able to investigate this. I hope that COVID-19 is not causing you too much trouble.

I have followed your instructions and have measured the resistance between each of the pads and the shields.

The pad nearest the top of the board measures ~2 ohms (which appears to be as close as my meter reads to 0 ohms), the pad nearest the battery measures ~40 ohms.

These readings are from my damaged board, which is what I understood that you were advising me to check - is that correct?

From this I presume that this means it was a capacitor?

Have you any suggestions about what I could try, to see whether a component might be replaced; difficult I know, given the lack of knowledge about what the component was

With kind regards

[Leo_TheCrafter]

That was likely a capacitor. The one side with 2ohm is GND and the ~40ohm is likely some core supply for the CPU. (VCORE?)

[NEast]

Thanks @Leo_TheCrafter for your quick response.

Presumably replacing this component is unlikely to change the non functioning rear speaker then. One assumes that there must be another fault somewhere that I have failed to spot?

Such a shame, since having had to use a S*ny for a few months, whenever I pick up the Fairphone I realise how light and good it is as a phone. Not to mention the root, modules etc etc. Not very usable with no rear speaker, sadly.

Any final pointers, or just recycle / fairphone angel the core module, do you think?

Many thanks for all your time and help. Extremely grateful.

[Leo_TheCrafter]

Maybe meassure power rails near the caps of the audio codec. There could be sth. wrong there. If not I would think that it is the I2S between the CPU and the audio codec. You know the drill: Take off, clean, reball, solder back on, and that for CPU, RAM and the audio codec. Have fun, but it could still be some issue with the power rails. I would try that