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Two iPhones with shorted capacitors above CPU

I have two iphones, one iphone 6 and one iphone 6S that both have a similar problems.

Neither will turn on.

When you connect a battery and charger both get very hot in the CPU area, mostly at the top of the CPU.

Almost all of those capacitors that are in a row directly above the CPU measure short, but the short remains after removing the caps.

I tried freezing the board with freeze spray and injecting 1.8v into the short. The only thing that melts quickly is whatever component I inject into, and then the CPU shortly after.

If I freeze the board and then connect the battery and charger, one of the coils directly above the CPU gets hot FAST. But there is no path to ground there, so that's confusing.

Any idea?

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Postato: 8 feb 2017

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The row of capacitors above the CPU in the iPhone 6 vary in function. Some are for PP_VCC_MAIN while others are for PP1V2_SDRAM and PP0V95_FIXED_SOC. However, what's interesting is that underneath that area on the logic board is the PMIC, the main voltage regulator for the phone. Chances are there are one or more shorts causing this chip to overheat and you may only notice it on the top side (CPU).

If you have a short on PP_VCC_MAIN, using freeze spray doesn't really help. That rail goes all over the board and it initially goes through the MOSFET next to Tigris...which is the component that unfreezes first.

You will have to take a much more patient approach to this. You will need to verify every line from the PMIC, plus PP_VCC_MAIN, PP_BATT_VCC and PP5V0_USB. Identify which rails are shorted (truly shorted - ~0 Ohms) and then look at all of the capacitors on those rails. It can be very tedious work.

Also do a visual inspection to see if there are any tiny solder balls shorting out two components...this does occur.

The same applies to the iPhone 6S, they have similar layouts.

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iPhone 6

Two iPhones with shorted capacitors above CPU

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