Way for solve iPhone 6S turn on failure

Fault Description: iPhone 6S happens something wrong on phone motherboard which lead the turn on failure.

Possibility Reason: According to the customer said, he dropped his phone into pool accidentally, so we doubt there may happen a short circuit.

Then, let us start the repair procedure.

Dissemble iphone with iphone opening tool , we saw that the motherboard was flooded with water, we cleaned the water area thoroughly, it seems that CPU Upper also exist fault. After tested resistance and powered on, there is no short circuit. Connect the iphone motherboard to the DC power supply, we find the current value is about 240MA.

Picture 1

Test PP-VCC-MIAN with a digital multimeter , exist phenomenon of short circuit, the resistance is small, only dozens of ohms. Observe carefully, we found that capacitor next to the WIFI chip was black seriously.

Use QUICK 861DW Hot Air Station (VC194) to remove the capacitor,  resistance is tested more than 100 ohms, and the current measured is also more than 100 mA. Due to the large water poured area, it was found that a capacitor on the iphone audio IC also became black seriously.

Picture 2

After removing the capacitor, measure PP-VCC-MIAN, then insert the DC power supply again, the current become more than 30 mA. Test multiple power supply, there is no short circuit, connect to the power supply, we feel a slight heat. So fumigate rosin in the upper part. It was found that power supply portion was hotter than other parts. After removing the display power, the current returns to normal.

Picture 3

After replacing the iphone power IC, the machine can be turned on smoothly, fault is removed, this fix work end successfully.

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