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Solved: iPhone 7P Screen Backlight Abnormal（half dark）


The iPhone 7 Plus screen backlight display abnormally, it displays half darkness, one side for the screen is darker than another side. After replacing the iPhone screen, the problem still the same. We need to check iPhone motherboard to solve the problem. 



Use screwdrivers to remove the screws next to the iPhone lightning port, put iPhone 7 Plus on the CPB screen separator to heat for a while, and then remove the iPhone display assembly, take out the iPhone motherboard. 

There is no water trace or pressure trace on the iPhone motherboard, fist to check the iPhone backlight part. 

Measuring the iPhone backlight pins of the display socket J4502 via digital multimeter, the data is 45, which is abnormal. 

Check iPhone 7 Plus schematic diagram via ZXW Dongle, we know that the iPhone backlight IC goes to j4502 Pin 45 by passing C4602, FL4601 and C4605, so we need to check C4602. 

Measure the diode data of C4602, it's normal.  Observe the iPhone motherboard via microscope, we found the pin 45 is virtual-welded. 

Carefully remove the J4502 from the logic board, can then test it again, now the data tested is normal. 

 Find a good J4502 from a iPhone junk motherboard, and then solder it to the iPhone 7P motherboard. After installation, measure the iPhone again, the data tested is normal. 

Now, we can install the iPhone 7 Plus. Press the iPhone power button, the white Apple logo displays normally, after entering the IOS system, the iPhone screen backlight displays properly, the repairs end!




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