Fix iPhone X high current problem

   This article will cover one of the problems that many iPhone users frequently encounter. As described by one iPhone X user, it cannot be turned on due to high current. Next, we will share how to fix iPhone X won't turn on due to high current.

   We first need to conduct a visual inspection of the motherboard, and it can be observed that the motherboard is not deformed or damaged by water. The motherboard can then be connected to the DC power supply and we can see that there is no current leakage. Judging from this, the three main power rails PP_BATT_VCC, PP_VDD_MAIN and PP_VDD_BOOST are in normal state.

   Next go ahead and start the motherboard with tweezers. We can see that the starting current is greater than normal. We can now determine that the fault may be related to the 17 supply rails of the PMU output.

   Now we need to detach the motherboard and confirm if the fault is related to the upper or lower layer. First put the motherboard on a special heating platform. When the temperature of the platform reaches the set temperature, carefully pick up the upper layer with tweezers, and continue to remove the lower layer from the platform.

   We can test the upper layers. Connect the upper battery connector to the DC power supply. Start the upper layer with tweezers. After starting it was found that the current was still greater than normal. We can now confirm that the failure is related to the upper layer. Our next step is to check the 17 rails.

   Check from PP_CPU_PCORE. Locate to C2701, one of the test points for PP_CPU_PCORE on the bitmap. Diode mode measurements of capacitors were run on the C2701 associated circuit. The measured value is normal. Continue to measure test points for the remaining 16 rails. Judging from the measured value, PP3V0_NAND is short-circuited.

   Since there are many components on PP3V0_NAND, we can use rosin detection to locate faulty components. Dip a soldering iron in some rosin and smoke the rosin on the components on the PP3V0_NAND. Adjust the output voltage of the DC power supply to 3V and connect the black probe to ground. At the same time, touch the red probe with the capacitor on PP3V0_NAND. We can see the rosin on the C2649 melted immediately. Judging from this, it is C2649 damaged.

    It is now confirmed that the short-circuit condition was caused by a damaged C2649. However, we also need to test the upper layers. Remove top layer and clean with PCB Cleaner. Connect the upper battery connector to the DC power supply. Start the upper layer with tweezers. The current is normal this time.

   What we still have to do is solder the two layers together.

   First remove the lower layer of thermal insulation glue. The lower layer is then placed on the heating platform. Power on the heating platform and apply Paste Flux to the third space PCB to get the upper layer in place.

   Finally, power off the heating platform. Remove the motherboard from the platform and allow the motherboard to cool for 2 minutes. Install the display components. Connect the battery connector to the DC power supply and use tweezers to power up the motherboard.

   The boot current is normal, and the mobile phone displays normally.

   iPhone repair problems are shared here. If you want to know more about phonefix, please comment below.