Monday 30 March, 2020 |

Solution: iPhone 7 won't turn on (leakage)

The iPhone 7 doesn't respond when we press the power button, after measurement, it's found that the iPhone 7 won't turn on. Use USB charge and iPhone lighting cable to charge the iPhone 7, the iPhone 7 is still won't turn on. How to fix it? Here is a solution.

Use phonefix screwdriver to remove the iPhone screws next the iPhone lightning port, put the iPhone 7 on the CPB screen separator to heat, after a while, use screen sucker and pry tools to open the iPhone screen.



Disconnect the iPhone battery, and connect the iPhone 7 to the DC power supply, the current measured is abnormal, it leaks 536mA.

Based on our repair experience, for this case, generally caused by two reasons, one is caused by the component that is powered directly by the iPhone battery is damaged, and the other is the connected circuit of the iPhone motherboard main power that converted by the battery voltage is shorted.

Use Fluke 17B+ digital multimeter to measure the iPhone motherboard, when measured PP_VDD_BOOST, it's found that the diode data of the PP_VDD_BOOST is abnormal, which is short circuited.



Use soldering iron to smoke some rosin to the motherboard, and then supply power to it, it's found that the rosin on a capacitor melts first.

Now use DES H92 soldering station to remove this capacitor, and use digital multimeter to measure it again, the diode data measured is normal. Then use DC power supply to measure the iPhone 7 motherboard, the current measures is normal.



Assemble the iPhone 7, press the power button, the iPhone 7 is turned on properly.

by Bellin

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