Chosen Solution
Hello all, I have a iPhone SE which went through a 15 minute laundry cycle. After removing it from the machine I opened it up right away and disconnected the battery. I then dried it all out and removed the logic board. I then proceeded to remove the shields and found humidity all over the logic board. After being certain everything was dry I tried powering on the phone but nothing happened. This was when I red up about cleaning the board with a ultrasonic bath. I have access to one at the place where I work so I used it with de-ionized water, seeing as how I didn’t have any electrical cleaner. The board was set in the bath four times for a duration of approximately 60 minutes each time. After each cycle I cleaned the board with isopropyl alcohol and a tooth brush. I don’t have a stereo microscope so I used a set o jeweler magnification glasses in order to check for any corrosion and shorts. The board looked very clean, almost like new. Finally I managed to get the phone to turn on completely and charge up. After charging up completely I left the phone on my desk for a while and pulled all of the old information off and updated iOS. The phones works normally, however I noticed the battery drains very quickly and the phone will randomly restart when the battery is between 100%-75% and 1% and 10%. The gyroscope also doesn’t work, the compass is “frozen” and will not move, however this doesn’t really bother me much, for now. I did all of the usual hard reset, DFU mode and iOS update but the battery drain and compass remain the same. In the process I let the battery charge completely and checked the voltage, 4.32 VDC. I kept checking the voltage without ever connecting it to the pin connector on the board, the voltage remained the same which indicated to me the battery may not be the culprit of the fast drain. I decided to use the phone for a while and soldered the shields back on and called it good. More reading/youtube videos and I decided to check the board for any possible short. I had access to a power supply so I set it to the fully charged voltage of the battery, 4.30 VDC. Placing the positive lead on the positive terminal of the battery connector and the negative on chassis ground, there is a current of 0.043 A or 43mA, however the voltage never drops. A short is always a short regardless of the amount of current that is getting through, however my question resides in the fact that the phone functions “normally” aside from the battery drain and random restarts. (I don’t feel anything getting warm.) I don’t have any freeze spray, would a upside down can of compressed instrument cleaning air work? I also tested the board with a multi meter. There is no continuity between the positive terminal and chassis ground and the diode mode reading with negative lead on the positive terminal of the battery connector and the positive lead on the chassis ground is 0.390V. (I’m not sure of the values that would be normal for a perfect board??) I have attached some pictures of the tests with the power supply and diode mode. I’m afraid I don’t know which way is out of this rabbit hole. Power supply test:
Multi meter diode test:
Any help or suggestions would be greatly appreciated.
Good work! However water damaged devices are, by nature, rabbit holes. Some can fixed easily, others never ever get back to 100%. You ask a lot of questions here so I’ll try and address most of them: Ultrasonic Bath. De-ionized water is fine but 4 X 60 minutes baths is too much. I usually run mine 5 minutes on each side in EC solution at 55 degrees and that is usually sufficient. The reason I do it quickly is that the EC solution can cause some corrosion due to dissimilar metals on the board. With de-ionized water you don’t have that issue but there’s no need to keep it in for that long. The bath is also the reason why your sensors no longer work; the cavitation causes issues with the delicate sensors inside these IC’s.Freeze Spray. Yes you can use an upside down compressed air can, some folks say it is even cheaper. However the material used to propel the air is not the same as a true freeze spray can and may have some conductivity issues (I’m not a chemist :>).43mA. So you see 43mA on the DCPS when connected to the battery terminals. Is this during the entire boot process or does the phone not boot properly on DCPS. I am a bit confused by this observation because earlier you say that otherwise, the phone boots and works okay. It cannot do that on 43mA.Diode reading of 390. Yes, that is a good reading. Besides, if the batt voltage rail (PP_BATT_VCC) was bad, the phone would not boot at all. Ultimately, fast battery drain can be caused by a faulty Tristar IC or a damaged subsystem which is simply draining excess current but not critical enough to impede the phone from booting and otherwise working. The only way to get to the bottom of this is to start probing beyond the battery terminals. Download the schematics (sorry, we can’t share them here) and look for the PMIC (U2000) and start probing all of the output voltage rails; you may find something amiss. However, keep in mind that this is a water damaged phone and all bets are off. You already recovered your data first, which is smart, and you did this for free! Everything else is gravy at this point.
Wow, thanks for the answer, I really appreciate it. I’m from an electrical background, however not electronics, a lot of research has been done to gain such little knowledge, haha. When I removed the shields, I noticed some corrosion on the board. I then ran the bath and cleaning with alcohol until the could see all of the affected areas cleaned. Ok, I can see why the gyroscope IC may be faulty now, oh well. After the bath and cleaning, I managed to get the phone to boot flawlessly. The phone works without any issues aside from the random reboots and fast battery drain, (Lasts less than 24 hours). As a tentative fix I updated IOS, hard reset and DFU mode all to no avail. More research was done, this was when I decided to check for a possible short on the board as culprit. Took the board out of the phone and placed the positive lead of the PS on the positive terminal of the battery connector of the board and the negative lead of the PS on a ground chassis point of the board, as per the picture. There was a current draw of 43 mA and no voltage drop what so ever, can this be indicative of a short on the board somewhere? Generally speaking I know how to define a short to ground, but in the “cell phone repair realm” I don’t know what to expect. Regarding the diode reading, thank you for clarifying the value is within normal. I managed to get a copy of the schematics yesterday and can see the PMIC U2000 handles everything power distribution related, hence the name
