System for fault determination for electronic circuits

A system for testing electronic circuits, comprising:

• a positioning system for mounting a circuit board or device previously operating properly but no longer operating properly, the circuit board or device having circuit elements thereon to be tested, the positioning system also mounting a sensor assembly, said positioning system capable of moving the sensor assembly in X, Y and Z dimensions relative to the circuit board or device;
• a control system for the positioning system for registering a position of the sensor assembly relative to the circuit board or device to be tested and for moving the sensor assembly to selected known locations for the circuit board or device to be tested;
• a sensor assembly for obtaining noise emissions generated by the circuit elements on the circuit board or device being tested at the selected known locations, the noise emissions being produced by the circuit board or device while the circuit board or device is in circuit under normal operating circuit conditions, the noise emissions being unrelated to operating signals of the circuit board or device;
• a spectrum analyzer for receiving the noise emissions from the sensor assembly and producing frequency spectrum information present at the selected known locations over a selected frequency range with amplitude information at selected frequencies within the selected frequency range, wherein the system includes frequency spectrum information from a separate circuit board or device known to be good relative to the circuit board or device being tested;
• and
• a processing system for comparing the frequency spectrum information obtained at the selected known locations on the circuit board or device being tested with a separate frequency spectrum information from the separate circuit board or device known to be good, generating a difference therebetween, and providing information to a user whether or not the difference is within an acceptable range of difference, wherein the difference not within the acceptable range of difference is an indication of the circuit board or device having a fault preventing proper operation of the circuit board or device.