Here is an iPhone 6S doesn't boot because of short-circuited, how to troubleshoot it? The trouble described is that the iPhone 6S accidentally fell into water, and then it has no response when we press the iPhone power button, we need to fix it.
Use screwdriver to remove the screws next to the iPhone lightning port, put iPhone 6S to the CPB screen separator, after heating for a while, we can open the iPhone LCD screen smoothly. Remove the iPhone display assembly, disconnect the iPhone battery, and then remove the iPhone motherboard.
Put iPhone motherboard under the microscope to observe it, we found that the iPhone baseband power IC, NFC IC, iPhone big audio IC and iPhone display power IC all have traces of water.
Use QianLi IBrush and PCB cleaner to clean up the iPhone motherboard, connect iPhone motherboard to the DC power supply, it leaks 80mA, after triggering it, the current stuck on 300mA. At the same time, we found the corners of the iPhone display power IC were broken.
Remove the iPhone display power IC, measure the iPhone motherboard again, now it's not leaks. Trigger it, the current stuck on 240mA.
According to our experience, the current reaches to 240mA after triggering, possibly it's due to there is a short circuit area on the LDO power supply that outputted by iPhone main power.
Use digital multimeter to measure the diode data of the LDO power supply outputted by iPhone main power, we found that the fingerprint 3V power supply is shorted.
Apply some rosins on the fingerprint 3V power supply area, and then use QUICK 861DW hot air rework station to blow it till it turns white, now add 3V to the fingerprint 3V power supply, we found that the rosin on a capacitor melted.
Check iPhone 6S schematic diagram via ZXW Dongle, we know that this capacitor is C4104. Directly use hot air gun to remove the C4104.
After removing, use digital multimeter to measure the diode data for the fingerprint 3V power supply, the value is back to normal. Use DC power supply to measure it, the current also is back to normal.
Now, install the iPhone 6S, press the power button, the iPhone 6S can be turned on normally, the trouble has been solved!
Use screwdriver to remove the screws next to the iPhone lightning port, put iPhone 6S to the CPB screen separator, after heating for a while, we can open the iPhone LCD screen smoothly. Remove the iPhone display assembly, disconnect the iPhone battery, and then remove the iPhone motherboard.
Put iPhone motherboard under the microscope to observe it, we found that the iPhone baseband power IC, NFC IC, iPhone big audio IC and iPhone display power IC all have traces of water.
Use QianLi IBrush and PCB cleaner to clean up the iPhone motherboard, connect iPhone motherboard to the DC power supply, it leaks 80mA, after triggering it, the current stuck on 300mA. At the same time, we found the corners of the iPhone display power IC were broken.
Remove the iPhone display power IC, measure the iPhone motherboard again, now it's not leaks. Trigger it, the current stuck on 240mA.
According to our experience, the current reaches to 240mA after triggering, possibly it's due to there is a short circuit area on the LDO power supply that outputted by iPhone main power.
Use digital multimeter to measure the diode data of the LDO power supply outputted by iPhone main power, we found that the fingerprint 3V power supply is shorted.
Apply some rosins on the fingerprint 3V power supply area, and then use QUICK 861DW hot air rework station to blow it till it turns white, now add 3V to the fingerprint 3V power supply, we found that the rosin on a capacitor melted.
Check iPhone 6S schematic diagram via ZXW Dongle, we know that this capacitor is C4104. Directly use hot air gun to remove the C4104.
After removing, use digital multimeter to measure the diode data for the fingerprint 3V power supply, the value is back to normal. Use DC power supply to measure it, the current also is back to normal.
Now, install the iPhone 6S, press the power button, the iPhone 6S can be turned on normally, the trouble has been solved!
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