Because it is a water damaged phone, so we doubt whether it has caused short circuit. Connected with 80ma, measuring result is 0.8v;Removing the iPhone USB management IC (U1700), iPhone display touch IC (U1501) and replacing PMU, the result is same, as the resistance value;We can judged it is not short circuit. Then we removed the CPU, the reset value is normal 1.8 which lower again after installing reset voltage.
Fine, We can judge it is caused by iPhone CPU. The reset pull-up resistance R0206 is 100K while the voltage becomes 1.6 after the change of the 2.2k resistance.
The upper cover current is a little higher, and the iPhone screen is not displayed when install to test the iPhone 6 device. The power supply required for the measurement screen is normal, connect Ace assistant which shows "please unlock the device", so it indicates that the system has been entered, and the failure is from CPU. Then PP1V0 is measured short circuit, a few points on CPU are all short circuited. Now, we have to install the CPU back.
Directly connect 1.0V to this point, the current is 350A and the voltage is 0.8V. It seems hopeful, so we connect it with PP1V2_SDRAM directly.
After we finished the above operation, we can see the iPhone6 turns on a bright screen. Though the current is about 400mA, the data is kept.
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