F-22 CATS application to the thermal cycling stress screen of self-testing, liquid flow-through LRMs

The application of the F-22 Common Automated Test Station (CATS) standards to the development of an effective thermal cycling stress screening (TCSS) system for the Line Replaceable Modules (LRMs) of the F-22 Common Integrated Processor (CIP) demonstrated the versatility of this COTS open architecture approach in the solution of this uncommon ATE requirement. The liquid flow-through cooling approach utilized by these modules negated the effectiveness of the most common TCSS approach in which the ambient air temperature within an enclosed test chamber is varied, and instead required the TCSS CATS station to manage the temperature profile of the module cooling liquid. The station was, of course, also required to provide the usual command and control of the test instrumentation while providing extensive management of the individual module test histories. The resulting system achieves high predicted screening effectiveness while allowing maximum manufacturing flexibility for six (6) module types in sixteen (16) individual test locations. The key to this flexibility is a unique backplane assembly which takes maximum advantage of the modules unusual ability to both test and fault isolate themselves.