A8 CPU short circuit: iPhone 6 Plus display black screen

Apple iPhone A8 CPU short circuit causes iPhone 6 Plus display black screen. It can receive calls, just the iPhone screen has no display. Now, try to fix it!

First, measure the working condition of iPhone LCD display IC, all is normal. Then measure the display socket J2019 with Fluke 15B+ Digital Multimeter, we found the #3 pin is short circuit. 90_AP_TO_LCM_MIPI_DATA3_N MIPI image transfer data bus leads directly to CPU, the initial diagnosis is that the CPU is continuous tin or internal damage. Second, remove iPhone CPU and then measure this signal line, we found it is the earthing short circuit, which is CPU internal damage, the kit is damaged. 6P and 6 are not the same size; the circuit design is also not the same. By analyzing the WUXINJI schematic diagram, we found the solution.

Third, According to the comparison of Feiying schematic diagram, we found that iPhone 6 Plus has one more a set of MIPI image transfer data bus than iPhone 6, 90_AP_TO_LCM_MIPI_DATA3_P、90_AP_TO_LCM_MIPI_DATA3_N, and iPhone 6 doesn't have that line. Because the iPhone 6 only needs to display 4.7 inch images, but iPhone 6 Plus needs to display 5.5 inch images. The faulty iPhone 6 Plus is 90_AP_TO_LCM_MIPI_DATA3_N short circuit, we decided to abandon the 5.5 and install the 4.7 directly.

Finally, install the CPU on this fault board to iPhone 6 motherboard, then assemble the iPhone by screwdrivers. After testing, the iPhone LCD screen can display normally.