Received an iPhone 6 Plus need to repair.
The iPhone 6 Plus LCD screen has no display and no light, it changed
the kit before. Now, we need to solve this problem step by step.
1. 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.
2. 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.
3. According to the comparison of WUXINJIschematic 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.
4. 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. Move the CPU on this fault board to iPhone 6 motherboard, the iPhone LCD can display now！
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