As we know in most the components of electrical equipment age during their operational life, which can be more or less long depending on the nature and degree of stress to which they are subjected, resulting in a degradation of performance to improve the reliability of the system. Industrial applications the DC machines are powered by a chopper voltage source. These machines are sensitive to different types of defects occurring to switches, capacitors and coils the need to conduct studies for the detection, localization and maintenance of defects become crucial. To avoid serious faults in DC-DC converters, several concepts have been applied to the diagnosis of these. The ANN method is used to diagnose DC-DC converters.