Released on September 19, 2014, this 4.7" screen iPhone is the smaller version of the iPhone 6 Plus.

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U2, battery problems, U2, logicboard problems

Hello,

could you pls give me a guide to change the u2 chip.

I have a problem with my battery. I bought an old second Hand Phone.

I have an iPhone 6. But i do not find any instrcution.

I bought an new Akku. But the iPhone has still some problems. After 10 hours of doing nothing, the iPhone is empty.

If I do nothing, It is not really hot. It feels a little bit warm.

It is possible that the Akku I bought has some problems, but is it also possible that there are other problems?

Do you know how I can solve that problems?

1. could it be the not original display (not from ifixit)

The guy before had a cheap Chinese battery and a Chinese display and he was loading the akku with a really cheap recharger. I throw it in the garbage can.

2. could it be the u2 chip ( I don't know anything about it, I heard only sth about this)

3. could it be the Logic Board?

If someone has some possible solution.

It would be perfect.

(I Hope you understand me, I am from Germany. But I think the English community is more strongly.

So I try my luck here ;)

thx a lot.

Answered! View the answer I have this problem too

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10 hours of doing nothing, the phone could still be receiving signal it could have a connection to wifi it could have bluetooth turned on, I don't know if anyone really does leave their phone alone for 10 hours and not use it lol

Anyway try a new battery before anything to do with u2 lol

U2 really Tristar is a usb controller ic on the phone it requires average skill with a hot air rework station at least to change it so do not attempt anything with Tristar also is the phone charging ok???

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Thx a lot. I am sorry.

Akku = battery (this is the German word)

So Micro-soldering means it is not possible to do this by myself?

I already made an battery test with IbackupBot.

This Is the result of the test:

Cycle Count: 3

Designcapacity: 1810

FullChargeCapacity: 1900

So this means the battery does work, doesn't it?

So the solution is to sell the iPhone?!

Another last question:

Is it possible that the reason is an cheap Display and it absorbs so much energy. I have also a display error (a blue 1cm big point) thx for the fast answers.

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3 Answers

Chosen Solution

What's an Akku?

If you have access to a USB Ammeter, you could use that to determine if the phone is really drawing current when it says it's charging.

To see if the battery is at the end of its life (assuming it will boot), use a battery utility, such as coconutBattery (for Mac) or 3uTools (for Windows). It will tell you what the health of the battery is. Anything less than 70% of design capacity will require replacement.

Depending on the symptoms, you may have a charging circuit problem on the logic board (that's what U2/Tristar does) but that would require a micro-soldering repair and is not DIY. Get back to me with more details.

EDIT

Several things can cause Battery Drain issues. You will need to isolate some variables in order to get a better understanding of what is wrong. The problem could be a bad replacement battery, excessive current draw from on of the modular components (camera, button, screen) or it could be a problem on the logic board itself.

Here are some things to try:

  • It could be a bad replacement battery; there are lots of cheap batteries on the market.
    1. Try replacing with a known-good battery or order a good one from here.
  • You could have excessive current draw from one of the modular components; for example, the backlight, a camera or a sensor. You may notice a hot spot on the phone or screen.
    1. Fully charge the battery first.
    2. Disconnect the battery, then disconnect the flexes for the screen assembly, buttons and cameras, leaving only the Lightning Dock connected to the logic board (follow this guide). When you are done, re-connect the battery.
    3. Go back after an hour or more and test the condition of the battery. You will need to download either coconutBattery (Mac) or 3uTools (Windows) to see the battery condition.
  • It could also be the Lightning port so you could try the same test as above but with the Lightning port disconnected once the battery is charged (connect it back to test the condition of the battery).
  • You may have a damaged logic board. This will require a micro-soldering repair and is not DIY. Drops, bends, water damage or using poor quality charging bricks and cables, can cause this.
  • Do a thorough visual inspection, preferably with magnification, of the area surrounding the battery connector.

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after going through your post again and again, i think i understand what you mean. if i get you correctly is that the battery don't last long. ??

if the logic board is not over heating and the phone is not hanging up, then there is no way the battery can drain really fast. so for this reason i will suspect that the fault is from the battery.

for the display test.

charge to 100%

step 1. let it stay idle/sleep for 3 hours with airplane mode, turn off all background running app. off wifi. then check how many % drop.

charge again to 100%

step 2. remove display from logic board. power it on without display. let it on for 3 hours. but back the display and then check how many % drop.

i guess you will figure that out. from battery problem

from there you can figure it out.

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@phoneebola why did you repeat your answer as a comment on my answer?

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Thx a lot. I am sorry.

Akku = battery (this is the German word)

So Micro-soldering means it is not possible to do this by myself?

I already made an battery test with IbackupBot.

This Is the result of the test:

Cycle Count: 3

Designcapacity: 1810

FullChargeCapacity: 1900

So this means the battery does work, doesn't it?

So the solution is to sell the iPhone?!

Another last question:

Is it possible that the reason is an cheap Display and it absorbs so much energy. I have also a display error (a blue 1cm big point) thx for the fast answers.

by

Yes, your battery is fine. Check my edited answer above.

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you have said so much but you haven't said anything.

Edited:

after going through your post again and again, i think i understand what you mean. if i get you correctly is that the battery don't last long. ??

if the logic board is not over heating and the phone is not hanging up, then there is no way the battery can drain really fast. so for this reason i will suspect that the fault is from the battery.

for the display test

charge to 100%

step 1. let it stay idle/sleep for 3 hours with airplane mode, turn off all background running app. off wifi. then check how many % drop.

charge again to 100%

step 2. remove display from logic board. power it on without display. let it on for 3 hours. but back the display and then check how many % drop.

i guess you will figure that out. from battery problem

from there you can figure it out.

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Ok. So it is possible to turn on the phone without a display? Didn't know that.

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@refectio unable to delete the comment. it was meant for answer

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No worries, just wondering why. You can always delete your comment. Just hover over it and you will see the delete option appear in the lower right hand corner of the comment.

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that features only appeared from pc and not from mobile. but that of answer appeared from mobile.

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Ok, i am running the first test at the moment. How can I see that the phone is started if i do not have a display or anything. Is there a small light or something else? :) Thx for help

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I hope i understood it right. First I run for 2 hours the Iphone with display. (I lost 10% in airplane mode and I did nothing with the phone)

Now i dismounted the display and plugged it into my PC. But my PC does not see the Iphone.

Is it possible that I plugged out too much and now there is no current circuit? Is this possible?.

There is the picture the phone looks like now.

Thx a lot

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OK wait. Now i see my phone in the PC. I see the internal storage and the used space. But i cant see my photos. I think i have to accept it in the Iphone, but I cant without a display. So this should be Normal. Thx a lot. Now i unplug my phone and wait 2hours. After that i wil give a new reply.

:) thx

by

10% in airplane mode that's ridiculous.

ok. In itools double click your iphone screen. the itools is just a mirror. which transmit your current touch screen display. but because you dont have your touch screen anymore to work around with your phone, you cant see much on the mirror. if the mirror is just blank in there its because of the sleep mode. so just press only the power button on/off to see display. That's all.

OK glad it already worked.

Await for your update for the last test.

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Ok I am back. The two hours are over. I dont understand it. Now i unplugged the display and the battery said 84%. so it lost more percent than before with the display.

Now i know that the problem is not the china display. But I also think its not the battery.

What else could I do?

thank you for the information I have received so far.

by

A friend of me will give me for a short time a battery. I will try this battery to be 100% sure that the problem is not the battery.

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ok. thanks for the update

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