Generally measure the on-circuit voltage of each component, and determine whether the circuit works normally or not through analysis. In line resistance can also be measured and compared with normal data. Disconnect the power supply and discharge the capacitor before testing. After measurement, the suspected damaged component is separated from the circuit and measured separately. Due to the limitations of the table, many measurement results can only be used as a reference and cannot be used as a conclusion of the quality of the component. There is a basic principle: what is good does not necessarily work; What is bad is bad.
It is recommended to measure the voltage of each pin of the chip, and then look up the information online, and compare and analyze the actual number measured.