Firstly, the step-down circuit was measured, and it was found that there was a resistance between the capacitors connected at both ends of the charging step-down inductor, so a rich inductor was replaced.
It is found that there is a resistance between the capacitors connected at both ends of the charging and buck inductor. Replace a rich inductor, start the test, and everything is normal.
Xiaomi 6x mobile phone does not charge after charging for a few seconds. After replacing an Inductor, the fault is repaired.