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Are You Confused with iPhone 6S Plus Charging Fault?

iPhone 6S Plus charging fault is a common problem that everyone might meet, recently, we received an iPhone 6S PLUS mobile phone, according to customer's description, he found it reboots frequently and regularly after charging at night, then it cannot be charged on the second day, it was sent to the store to replace the iPhone 6S Plus battery but invalid. Replace the charging tube, USB controller, field effect on the pipe short, and hit the ground resistance, we did not find any abnormalities. Replace the relevant iPhone IC, the failure can not be resolved. so we take out the motherboard immediately after receiving the goods. As shown in
picture 8-2-1.


According to the experience,  we judge the motherboard should be unable to detect battery data. Test the iPhone LCD assembly, press the boot button to trigger the boot function, we found LOGO get lighter than the normal device, enter into the system and connect Ace assistant, which really shows no battery data, CPU can not detect the battery. As shown in picture 8-2-2. Test other functions are normal, during the test process, the iPhone 6S Plus reboots every three minutes, it can be connected and there is a sign of charge, however, the power does not rise, it increased by 3% after unplugging the data cable, but immediately less than 3% when plugging in.

Immediately go to fix the device after the fault is confirmed, the ground resistance of the battery detection pin is measured first. As shown in picture 8-2-3.

After the measurement we found it gets normal again, USB controller and charging tube were replaced before, after the replacement of the fault is still existing. Then measure the sacred resistance of the charging pipe, and the USB controller's resistance to the ground, there is no fault.

Then I wonder if the iPhone 6s Plus CPU itself is damaged, measuring the charge tube to the CPU SIW to control the bus voltage, as shown in picture 8-2-4, as expected, the voltage is only about 0.8, and it's also jumping.

For iPhone CPU internal damage, this can only be tried by external power supply to the SWI bus pull up. As shown in picture 8-2-5. same failures also happen a lot on A8, this method is not 100% can repair, in the case of CPU is not completely damaged, it's also possible to be fixed.

Starting from a suitable place, pulled from C3620_RF main power supply over a series of 10K resistance to SWI_AP_BI_TIGRIS, as shown above picture. After the completion, install LCD assembly to test device, we found that LOGO lights faster than before, at this time we are going to connect Ace assistant. As shown in picture 8-2-6.

Now, the Ace assistant is able to read the battery information, showing battery life and charging times, as shown in picture 8-2-7. Continue to test the function, no reboot phenomenon, and the power can also be charged.
                         

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