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

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iPhone 6 not turning on. the cpu gets really hot

the cpu is heating up, there is probably a short somewhere around the cpu or in the cpu itself. how can i measure components with a multimeter to see which of them is the problem. i read somewhere i can't use a multimeter to check resistance because it will pass 9V and the components will fry is that true? if so then what should i measure for?

thanks

Update (11/02/2015)

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here are some pictures. looks normal to me

Answered! View the answer I have this problem too

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I am not sure where you heard this, but it's bogus. You did not tell us if anything happened to the phone or if this just all of a sudden started. What have you done thus far?

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the phone got smashed pretty hard. i removed the shields around the cpu. once the battery is connected and i turn it on the cpu gets burning hot until i disconnect the battery. i didn't do anything beyond that yet. i searched around the internet a bit, it might be the power management ic but i'm not sure on how to check and make sure thats the problem before i go ahead and replace it.

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You used a new battery? Checked for any visual damaged on the logicboard after removing the EMI shields?

by

yes i used a new battery it's not that. no visual damage on the logic board, it actually looks really good, nothing damaged or burnt. also cleaned it with isopropyl alcohol and the short is still there and the cpu is heating up.

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Post some good images of your logicboard with your question. that way we can see what you see.

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Deck the Halls
With tools and Fix Kits

2 Answers

Chosen Solution

Hellow Nadav,

Image 1 - A8 SOC and Image 2 - Main PM IC on logic board. i guess heat produce from the PM IC.

both chips were located at very closed upper and lower sides of the logic board hence you feel A8 get hot. Main PM IC doesn't drive RF directly as ordinary phone so checking on RF AMP/drives short circuit doesn't make sense to this case.

(Question )Multi meter - Multimeter probes produce narrow current to measure components on ohms range but it never enough to fry your motherboard components and its not enough to do things that statistic electricity of your body to damage hi e-sensitive components on logic board.

9V battery is use to power up the multimetter and it will not produce 9V though the probes for any case.

Reason the occurring these kind faults on apple devices

  • if you use 3rd party / apple not certified charger to charge your device
  • if the phone damaged by liquid
  • Low quality wires connected externally (Damaged) lightning cable
  • SOC, NAND Vbus 1.3V-1.8V short circuit

Solution : This fault is every complicated to rectify and you may required hi-tech tool to monitor signaling.

but can be recommended you to replace Main PM chip : (part number - Apple/Dialog 338S1251) it required high level BGA reworking skills to replace the chip. (Not expensive chip :-) you can order via eBay or amazon )

PM chip replacement was hard but some moved capacitor fixing was harder than Chip replacement. anyway fault is repairable.

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Buddhika Mahesh thank you for this answer, it's very informative. i ordered the PM chip and i will try this repair and report back

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i have checked to see if the PM chip gets hot too and it doesn't get as hot as the cpu (probably gets a little hot because of it's proximity to the cpu). could it still be the PM chip?

by

Nadav, PM chip is not expensive part but you need high level BGA reworking skills to do PM replacement. it's better if you can use IR rework station with heat sensor to do that. When replace the PM most of the time some caps will be moved so you need micro-soldering skills to fix them also. two time i failed to do PM replacement :-) anyway you are with dead body now, you can do any surgery you want.

by

Here i found PM replacement by ordinary reworking station ( not recommended ) but you can get an idea

"https://www.youtube.com/watch?v=GyAEL-4H... "

by

i'll just try and do this with my trusty hakko hot air station. if other parts move i'll snap them back into place. IR rework station is not a possibility at the moment but i'll start saving up ; )

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Nadav if you want to test the CPU supplies from the power management without blindly pulling random ICs the you should isolate the line via the inductor coils on the H7 buck rails as they are high ampere rails. Its not uncommon for for say a shorted cap to cause the CPU to heat. Isolate all faults by removing the inductors this will tell you if it is a supply or demand issue

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can u help me with something my iphone 6 motherboard lcd connectors are damaged and due to that or i dont know may be something else cpu is getting very hot i dont know how to fix it or what to dp?

can u please tell me?

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If your connecter is damaged and shorting the data lines this will affect the gpu cores in the CPU and it will heat the CPU. SDRAM shorts will also heat the ram package on top of the CPU. Don't start it up until you have the socket changed

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I dont know how to fix them can u do it for me?

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where are you based? as i am in the uk

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I live in India bro what should i do?

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Nadav will be eternally grateful.
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