Various embodiments for detecting a high Intensity radiated field (HIRF) in a line replaceable unit are provided. For example, an internal detector includes at least one antenna attached to a chassis. The at least one antenna is configured and dimensioned to pick up an electromagnetic field. The electromagnetic field induces a current in the at least one antenna proportional to a magnitude of the electromagnetic field. The internal detector also includes a circuit configured to generate a DC signal based on the induced current in the at least one antenna and a processing section configured to compare the DC signal with a threshold and output a result of the comparison to a built-in test section. The internal detector may be used to test EMI filter pin connectors of a closed line replaceable unit.