The methods described above find KEPI with short-circuited layers and conductors, but it is impossible to determine their exact location in the circuit boards by them. And since the cost of multilayer boards can be extremely high, it is not cost-effective to reject an entire board because of one defective part.
There is special modern equipment that uses the “vector search” method. Such a device supplies a voltage to the area with the alleged malfunction, with the help of which changes in the flowing current are monitored, and, based on this, it is revealed where precisely the defect is located. The accuracy of such a device reaches milliamps, microvoltmeters, and milliohmmeters.