The method of charged measurement mainly solves two problems. First, the problem will be subdivided, and eventually locked into the Printed Circuit Board components of the problem. Second, the problem has not been solved, and it is necessary to find out the cause of the fault through live measurement.
1.Power the Communication PCB. Some PCB board power is not a single, may need 5V, do not add the power leakage. After replacing the component, check whether the printed circuit board fault has been solved or not.
2.Measure the gate circuit on the PCB with oscilloscope to see if it is in logical relationship.
3.Use oscilloscope to measure the crystal in digital circuit, and see if it has output.
4.A digital circuit with bus structure, generally including digital, address, control bus. Use oscilloscope to measure the three way bus, compare schematic diagram, observe whether the signal is normal, find out the problem.