iPhone 4 – turn on problem , new ios

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iPhone 4 – turn on problem , new ios

On March 28, 2015, Posted by , In iPhone, With Comments Off on iPhone 4 – turn on problem , new ios

I have a problem Along with my iPhone, Its NOT water damage and NOT drooped, it simply, in a very bright day, just stopped working.

Ive succeeded to turn it on a few times but every-time it stays on for
about 1 or 2 minutes and then FreezeRestartTurn off .
I replaced 2 batteries and the same thing happens.

The only thing Ive successfully able to do is putting
it in DFU mode and it stays in this mode constantly Along without problems.

iTunes is recognized the iPhone in DFU mode and give me a MSG for
restoring it, when I hit Restore button its makes something
(Contact Apple and verify restore…) and after a few seconds
give error MSG 1602.

After reading some previous posts regarding almost the same problem
as mine I decided to check the battery ways contacts on the board
Along with a multimeter and it seems that everything is good as attach picture (By Wites).

because its not water damage and not dropped and the board looks like
new and very very clean I dont know whats wrong Along with it..

Any ideas?
Is there something I can testcheck?

No Comment so far:

  1. baybee says:

    Try a hard reset, and different cable, check dock connector, try different usb port or pc, check you have latest updated itunes.

  2. RandikPixie says:

    iTunes is updated.
    Hard rest not to be helpeded.
    Different cable not to be helpeded.
    Trying another PC not to be helpeded

    Checking dock connector? how?

  3. RandikPixie says:

    I guess its the CPU! title=frown

  4. julianz says:

    Clean motherbord & change an other good battery

  5. killu says:

    theres some pin unsolder in CPU brother

  6. wagny says:

    yes CPU try to rehot few sec good luck

  7. wagny says:

    Ill try to clean the motherboard (put it in alcohol bath for a few minutes).
    If it will not work then I dont want to tell you that messing Along with CPU could lead to
    a much much bigger damage.
    So if there is a way to determine that the CPU is the problem then I would like
    to test it before ReHotting .

  8. newComer says:

    I dont want make you sad…but maybe your problem comes from factory!

    I had a same problem a year ago. an iPhone4 suddenly stopped working, it was summer!
    When i tryed to restore, i get always an 16xx error. (this is mostly cpu)

    I inspected the CPU soldering balls Along with a BGA inspection machine. I saw that some contacts only given by pressure….the solder balls wasnt melt propery and they had only contact Along with the pressure between board and CPU. If the board gets a little bit hot and gets only a little bit deformed, the contact was broken and the phone wasnt able to start. I rehot the CPU Along with moderate hot air, and the phone worked again. But not too long! (for about 1 week). But the problem was clear, i saw at this time no secure way to fix this problem and told the customer to exchange the phone.

    But anyways, try to make a thetered boot wit redsn0w. Check also the PMIC voltages, if they are 0V as soon you connect the battery. Maybe the PMIC can also be the problem!

    BR Matthias

  9. Metaton says:


    I put the motherboard in alcohol bath for 2 hours while shaking it every 20 minutes.
    I used an air pomp to gently remove any alcohol left inside the motherboard and let it dry for 30 minutes.
    Then I assembled the mother board back and finally the iPhone come back to life showing me the recovery Mode (connect to iTunes picture) title=big and I was able to update to the new ios 6.
    The phone was updated and Ive been played Along with it for awhile…

    but 15 minutes later the phone Freezed and Turn off again. title=frown
    When I turned it on again it Turned off again after 3 seconds.

    It seems that cleaning the phone to be helped a little, but I cannot clean the phone every 15 minutes.
    Is this mean Along without any doubt that the problem is the A4 CPU ?

    1. What is your suggestion for rehot the A4 CPU? what temp should I use and for how long?
    2. how can I test PMIC voltages ?

  10. chugowa says:

    You could be lucky, it may be just a dry solder joint, get the schematics, and have a closer inspection of the board, also try unpluging the screen etc, and power on.

  11. TechGuru says:

    I tried to turn it on now again and this time it stays up for 5 minutes and then keep restarting… I already put this motherboard in another iphone and the same thing happen there so it looks like the problem is clearly the mother board and not one of the other components (screen, speaker flex cables…)

    I think the cleaning may not done anything at all and it just wanted to be turned off for awhile..
    1 week turning off = 25 minutes activity (was enough to update to ios6)
    1 day turning off = 5 minutes activity

    Im afraid to mess Along with the A4 CPU or PMIC or any balled chip, Ill rehot the A4 CPU chip as last resort.
    Any suggestion will be welcome.

  12. TechWorld says:

    check the voltages around PMIC first as follows:

    There are 3 coils parallel. Disconnect the Battery and connect again. Measure at one of the 3 coils the voltage to GND and press the power-button for 0.5 sec. The voltage must go up to about 1.2v and go back to 0v again. if the voltage stays, your PMIC has bad connections. if the voltage goes back to 0v, you have no other choice than rehot the A4 CPU. Dont use too much temperature or you can trash the board for sure. Try Along with 260 Celsius for about 20 seconds first and let it cool down well before you try again.

    Give Feedback and i wish you the best! title=smile

  13. Bo-Rens says:

    …better 15 seconds for the first try! Or what other guys mean?

  14. RandikPixie says:

    I checked PMIC voltages and they where good The voltage go up to about 1.2v and go back to 0v again)

    I prepared the board for Re-hotting, cover everything in aluminum sheet leaving just the A4 CPU uncovered.
    I Rehot the cpu for 15 seconds in temp 260 Celsius, let it cool for 20 minuets and reassembled in iPhone.

    Bad news: the phone now is not turning on at all! title=frown
    Not recognized by PC or iTunes.
    Hard reset not working, no sign of life..

    anything I can do from this point ?