How to fix the problem of mobile phone due to high current？

   When using a mobile phone, it is inevitable that the mobile phone cannot be turned on due to some problems. It may be that the book machine cannot be turned on because the current is too large. Let's take Iphone 11 Pro max as an example to learn how to fix the problem that it cannot be turned on due to high current.

   High current is one of the common problems in mobile phone repair. Due to the large number of components involved, it is difficult to detect damaged components. This is where thermal imaging cameras are needed, which are often used to quickly detect faulty parts.

   LINCSeek SuperCam thermal imaging camera mobile phone motherboard PCB fault detection, use the one-key power cable to power the motherboard, adjust the display mode to thermal imaging mode, and enable the software quick check function to detect faulty parts. Simple operation to quickly help find faulty parts

   First, lift the screen and disconnect the battery. Connect the motherboard with the power cable. When the ammeter shows a current of 1 amp and does not trigger the power-on, the current of the mobile phone is relatively large. Therefore, it can be judged that the fault lies in the main power circuit and related components.

   Next, remove the phone motherboard. Use a multimeter to measure the diode value of the battery connector. The diode value is normal, put the motherboard on the thermal imager. Connect the motherboard with the power cable. The area around the NAND is getting seriously hot. Since NAND is not on the main power supply circuit, we need to separate the motherboard for further testing.

    Then connect the logic board with the power cable. The logic board does not have a large current. Then the fault may be on the signal board. Use the probes of the multimeter to power up the signal boards individually. There is a large current on the signal board. It can now be confirmed that the fault is on the signal board. Put the signal board on the camera and power up. The temperature in the area around the U5000 quickly reaches 80°C.

   Next use a multimeter to measure the capacitance around the U5000, there is a short circuit. In addition, the capacitor was found to have burned out during the measurement. Next, we remove the capacitor. Apply some solder paste on the capacitors. Remove the capacitor with a heat gun at 380 °C and replace it with a new one. Measure again with a multimeter. At this point, the diode value returns to its normal value of 446.6.

   Heat the signal plate on a 170 °C heating platform. After the solder balls have formed and the board has cooled, apply some flux to the pads.

   Align the logic board. Continue heating with the heating platform. After the motherboard cools down, connect the motherboard with the power cable. Trigger boot with tweezers when the motherboard no longer draws high current. The starting current has returned to normal.

  Install the phone motherboard. Press the power button and the phone will turn on normally. So far, the problem that the mobile phone cannot be turned on due to the high current has been solved.

   According to the above description, if your phone cannot be turned on because of this problem, you can try this method to solve it. If you need repair tools such as thermal imaging cameras, you can buy them from our China Phonefix Shop.