After we got the iPad Mini 2, we disassemble it without any doubt, cuz there absolutely no display and no any backlight, the key is that it was dropped into water.
Get the motherboard, and separating it from the shell, we need to check the power current firstly. After that, we start our observation.
Open the iPad Mini 2 to observe, we can see that the lower half of the motherboard is water damaged. Check the motherboard under the magnifying glass carefully. The power supply and the display interface are corroded badly.
First we deal with the power part, and then carefully deal with the display interface, because this iPad is the display and backlight problem, when finished processing, one of the resistors fell down, check the schematic diagram on WUXINJI dongle, we found it's the light IO data interface, this resistance is 1 ohm.
Picture 1
The ground resistance value was measured by Fluke digital multimeter at the display interface after the short connection with jumper wire. It was found that there were four places where the resistance value of the pin have no resistance value.
Short connect one by one, it has display but no backlight, so we concentrate on the high voltage side at this time, we found that the backlight positive pole and the interface are corrosive under the microscope, so we slowly scrape with a knife, and then weld with 0.01mm Jumper Wire, to prevent loose weld when install the display screen.
Picture 2
Install to test, the problem is solved now.
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