Techniques for diagnosing line replaceable modules (LRMS) on automatic test equipment

The author describes diagnostic techniques primarily used for line replaceable modules (LRMs) that have been tested using edge-connector, functional test techniques. A guided probe algorithm is introduced. Advanced guided probe features illustrate improvements to the guided probe algorithm. The author describes how a diagnosis is made from the failing LRMs fault signature. Modern fault dictionary features that are used to maximize the diagnostic effectiveness are described. The combination of guided probe and fault dictionary techniques is used to overcome the primary deficiencies of each. In addition, the use of a Smartprobe permits easy implementation and use of adaptive diagnostics to continuously improve diagnostic accuracy. The concept of combining the guided probe with knowledge of the boundary scan chain is introduced to reduce or eliminate the requirement for a handheld guided probe to diagnose faults.<>