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Guide: iPhone 6 LCD Screen Display Problem


Received an iPhone 6, the fault was that the iPhone sometimes display normally, but sometimes not. Open iPhone 6 to test, iPhone LCD display does not show anything. Removing the iPhone motherboard and looking under a stereo zoom microscope, it was found that there was a lot of solder paste in the socket of the iPhone monitor and the socket of the iPhone touch.

Is that the socket not clean? First we use BGA clean water to clean the iPhone motherboard, after cleaning, we can use digital multimeter to measure the grounding resistance value for the J2019 display socket 1 pin PP_LCM_BL_CAT2_CONN and 4 pin PP_LCM_BL_CAT1_CONN, these two pins will cause iPhone screen half bright and half black problem. We found the resistance value of 4 pin is 2111, which is abnormal, the normal resistance value is about 570.

After short connection of the FL2025 fuse inductor, the resistance tested is normal.


Assemble the iPhone display screen and test it, the Apple logo can be displayed normally, but the backlight still not bright. We noticed that the CPU shield cover was been moved, remove the CPU shield cover, we found the CPU was been repaired. Now, it's easy to explain, the U1502 backlight IC is virtual welded when blowing the CPU by QUICK 861DW hot air rework station, and it leads the iPhone LCD screen sometimes bright and sometimes not. Also, there are many solder paste and tin balls, which is easy cause iPhone motherboard to short circuit.


Clean up the tin balls and solder paste, and then remove the iPhone backlight IC. There is a good way to remove the iPhone backlight IC, remove the three filter capacitors above the backlight IC, and then the iPhone backlight IC is easy to remove.


Reballing tin and then install the chip, assemble the iPhone and test it, the fault has been solved.

If you want to get more cell phone repair tutorials, just contact us on www.vipfixphone.com

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