Detection process
Using the elimination method, first start the single board, first exclude the external configuration,
remove the motherboard connected to the regulated power supply, and perform the single board startup test.
The current jump of the startup test is normal.
The start-up current of the board jumps normally,
so the fault point is locked on the external configuration (As shown in the figure).
1. Put the motherboard back into the case to test, press the power button, the current jump is normal.
2. Install the screen on the motherboard, press the power button to continue the current jump at 226mA, the original fault of the mobile phone appears.
3. Change the screen, press the power button, the current jump is normal.
4. Install the handset cable, press the power button, the current continues to jump at 226mA, and the original fault of the mobile phone appears.
5. Remove the earpiece cable and observe under a magnifying microscope to see if there are signs of water ingress or cracks.
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