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iphone 5s with a charging issue and other strange behaviours?

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  • iphone 5s with a charging issue and other strange behaviours?

    I've purchased working iphone 5s's(at least that's how they're advertised!) off private sellers(ie original owners) on Ebay for the purpose of validating my microsoldering skills on iphone motherboards. I assume this strategy is relevant/has some relevance? to working on more recent apple boards(is this valid?). One phone however is less than perfect and already got me in troubleshooting mode..
    Observed behaviours as received
    (1) The right half of the screen is dimmed
    (2) Does not charge/is not recognised by the computer
    I reassembled the motherboard into the frame/parts of a 5s which tested AOK.
    (1) There is no dimming of the screen(so not a backlight issue?)
    (2)Always when Plugging into USB charger/computerI hear two successive sounds from the vibrator motor. This does not happen with the other 5s's I've tested. Phone IS recognised by and storage is readable by computer. When the phone is plugged into charger the charging symbol is displayed with 84% charge BUT(as read off USB ammeter) the phone is drawing low current ie 50 - 80mA only, battery level doesnot increase.Also, when the Screen times off current draw drops to 0mA - this does not happen with the other 5's I've tested- even at 98% charge the other 5s is drawing smallamps. Ok I know? I've got a charging issue on this motherboard. Do I assume Tristar is faulty or do I need to think a bit more?

  • #2
    definitely not charging/fake charging motherboard issue AND the original. (well I never!) charge port flex is faulty


    • #3
      Video of EMI shield removal attempt
      Now I have an issue with another 5s I purchased. I tested the phone prior and it was working fine (except for a non working home button which I already knew about). Last night after dissassembly I attempted to hot air off the EMI shield from the motherboard. I applied 450 degress celcius and 110L airflow from a 10mm nozzle(the largest I've got) from my Quick 861 station. I set the timer to 45s to abort in case I could not get the shield off in this time. I ended up aborting. Today I reassembled themotherboard into it's old frame. Now whilst trying to test the phone it reboots adhoc and the battery level it's reading is all over the shop. ie sometimes after reboot reads 64%, 49%, even only 1%.
      Is it reasonable to assume my hot air venture caused this damage?


      • #4
        Let me make sure I'm following you.

        Post one and two above: I have a phone that has nothing wrong with it after I tested with known good parts.
        Is that correct?

        Post three:
        I tried to take of the bottom shield on a 5s, aborted, and now I have gas gauge issues, did my hot air cause this?

        Answer: Probably not. I watched your video--you're doing great! Your instinct to stop because it was taking a bit too long is great--that shield removal was just about to cross to the danger zone at that time.
        So why didn't it come off? Answer--somewhere there was a sticking point. Next time, after you go around evenly, try to determine the "cold spot" that is keeping the entire shield on. It could also be a physical sticker--did you take off the little black sticker at the bottom of the board? The only feedback I have is --try again, and keep the hot air pointing STRAIGHT DOWN at the board. Get slightly closer to the shield with the nozzle.

        Your symptoms now are gas gauge--I can't read the battery data, so I report erratic battery percentages. This is MOST LIKELY bad battery, crimped battery flex, bad connection of the battery to the connector at the tiny data line pins, or you knocked off FL11 near battery connector. For a 5s, there really isn't any other mechanism of failure to explain battery data "gas gauge" problems other than those, and none of that is shield removal related UNLESS your battery connector is puffed up from heat and that's the reason the battery can't make contact.

        Keep trying, you're doing fine.


        • #5
          Hello Jessa. Thanks for the advice and encouragement.
          Post 1......................
          Testing phone as received - existing battery level 84%.
          Connected to a charger via USB ammeter
          1. No charging symbol
          2. 0mA current draw

          And not picked up when plugged directly into a computer.

          I tested the battery from this phone.
          1. Battery terminals measured 4v with the multimeter
          2. Took 2A amps charging current from DC power supply at 6v (DC power supply set at 2A limit)

          Taking motherboard out and transferring into known good parts**.

          Connected to a charger via USB ammeter

          1. Has charging symbol
          2. 50-80 mA current draw
          3. After 5 minutes battery level still 84%
          and picked up when plugged directly into a computer.

          Only noticed the 2 vibrator motor buzzes when connecting via USB
          second time round(can't remember if I heard when testing phone as received). Doesn't seem usual behaviour.

          What do I conclude from all this? I conclude there is a problem with the charge port flex AND charging on the motherboard. Is this wrong?

          **My definition of known good parts in this case is an assembled frame & parts that belonged to another iphone 5s which tested 100% working(including most importantly the charging aspect). I swapped out the known good board from this frame/parts and swapped in the unknown board


          • #6
            Okay, it might help to eliminate anything in a problem description that is not relevant to the problem at hand.

            Phone 1:
            History--unknown eBay.
            Boots as normal.
            With known good parts it does not consume normal charging current, but is recognized by iTunes.
            vibrator buzzes when plugged into usb

            Re: vibrator--this is what devices do to signify usb restriction. Maybe you didn't notice it before if you've been working on phones that don't have usb restriction enabled.

            Re: not charging. Is there a signature problem for board level 5s not charging that is very common? If yes--rule it out.


            • #7
              Post 3 response.
              (Still working on on your response to post 1)

              I looked to seee if FL11 was missing... and yes it was gone. I have been experiencing great difficulty dissassembling/reassembling this and iphones in general so must have pulled it off at some stage whilst struggling with the battery connector. Have since harvested FL11 off an iphone 6 board(iphone 6 FL2511). AND It has fixed the problem. Before you clarified this I was assuming Tristar had gone bad and my EMI shield removal attempt had caused it. I would never have guessed it was physical damage caused by myself flicking off this tiny coil. And this one has clarified to me how easily a user changing their own battery can cause this issue. A valuable learning experience all round. Thankyou


              • #8
                Post 3. Heat Shield removal. No I didn't remove the black sticker but did this time. This time I increased to the hot air to 500 degrees 120L airflow with 10mm nozzle, aimed straight down into the board and got in closer. I got the shield one third off at 40s and aborted. Allowed the board to cool down for 15mins and had another go. With the shield a third off I got a nice solid grip of it with the tweezers and did a bit of shaking The rest came off in 27s. Is this a legit way to do it?


                • Jessa_the_Professa
                  Jessa_the_Professa commented
                  Editing a comment
                  Sure, although after you stopped the first time it just means there is a single sticking point. You would have found it in another two or three seconds by trying to guess that the hold up was.