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  1. #1
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    Thumbs up iPhone 4 PMIC help/problem - looking for solution of iphone hardware



    I have a iphone4 that is constantly rebooting itself. It seems to do it whenever the cpu is working hard or the battery is charging. I cant go more than 1.5 minutes Along without it rebooting especially when charging. I captured the read out from the portal using the iphone configuration utility and is seems like the ADC in the PMIC is either bad or has a bad solder joint because it cant read the temperature of the board. I guess the kernel then reboots the board if it doesnt see the temperature after so long and thats why Im seeing these sporadic reboots.


    Has anyone else seen this or can give me advice on a possible solution? PMIC Pinouts etc?


    Thanks

    -Beall

  2. #2
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    Thumbs up iPhone 4 PMIC help/problem - looking for solution of iphone hardware

    what problem did you use for debug? However download the whole schematic here on the forum and probably reballing PMIC will solve your probs title=wink

  3. #3
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    Thumbs up iPhone 4 PMIC help/problem - looking for solution of iphone hardware

    it shorted, u have to find out where shorted so it will work again

  4. #4
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    Thumbs up iPhone 4 PMIC help/problem - looking for solution of iphone hardware

    maybe you can change the battery first , if you dont do this before



    about @ubreakifixit idea , will be nesesary to look at the capacitors arround PMU and try to find some shorted, the iphone 4 have a lot of problems Along with shorted capacitors , almost cases by water damage



    on the third scenario you may have bad solder on pmic or also in cpu , my advise , clean both sections Along with thiner and try, if not work you may have to desolder pmic and made a reball , also its glued on board , i recomend to use a preheater and hot air gun


    here in the forum exist some tutorials about reballing, and exist some interest made by wites about speed up reball Along without special equipment , but want hard skills to get sucess


    hope it to be helpeds



    in other hand, i agree too , kindly let us know which app you used for debug

  5. #5
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    Thumbs up iPhone 4 PMIC help/problem - looking for solution of iphone hardware

    Thanks for the advice guys,


    Im going to try the capacitor idea first and then maybe the reballing of the PMIC. Ive heard of similiar issues Along with the battery thermister going bad but the debug text clearly leads me to believe it is one of the PMIC thermister ADC channels that doesnt have continuity. I dont think it is the CPU because I feel like it would serially get the temp status of the PMIC chip from the PMIC through a data line. Therefore youd see more stuff not working.


    It is weird though because the CPU doesnt poll the PMIC for temperature all that often it only does it when charging or doing something CPU intensive. You only see it kick on after like a min of being on or so or almost instantly when charging. It will Keep requesting the temperature for about another minute and then it will force reboot the phone.


    Im using apples free iphone configuration tool for windows. After you connect there is a terminal button that will display the random errors or status reports from the phone.

    [Only registered and activated users can see links. ]


    Thanks again!

    -Beall

 

 

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