Hardware issues migrating legacy TPS to a new tester

In the late 1970's The Boeing Company designed and developed the 757 and 767 commercial airplanes. To facilitate production and return-to-service testing of the complex avionics used in these airplanes, the company contracted with Hewlett Packard Co. to develop an automated test system (ATS) used by our factory employees and airline customers. Hewlett Packard's ATS/1000 product line was chosen as a core test system and the result was the Boeing ATS-182 test system. In the mid 1990's a Boeing developed ATS-195 for the 777 commercial airplane supported production and return to service testing of 777 avionics. This paper discusses Boeing solutions for migrating test program set (TPS) to a new ATS. The paper combines test capability of two different legacy test systems into one new ATS design. These ATS are used for TPS development, production and return-to-service testing of complex avionics for commercial airplanes. Due to the increasing cost of operating the legacy test systems and the availability of obsolescence-tolerant instruments, and instrument drivers the business case justified the need to migrate to a new ATS. The new ATS uses a revolutionary dual tiered VXI interface that maintains signal integrity by reducing instrument and switching system cable lengths. A cost affective approach to use the legacy test unit adapters (TUA) on the new ATS is achieved by using an "adapter-to-adapter." An innovative printed wiring board (PWB) design is used within the adapter-to-adapter to reduce manufacturing costs and minimize variability. A frac14-inch thick, 30 layers PWB is used to minimize structural deflection due to the high pin count used for the dual tier interface and to provide proper signal separation. Challenges in creating proper impedance matching and signal grounding while maintaining the structural aspects of this PWB are discussed in this paper. Difficulties in finding commercial-off-the-shelf (COTS) solutions to match legacy switching systems and instruments are discussed. This paper discusses hardware challenges and solutions for these areas of common interest for legacy TPS migration to a new ATS as well as support and variability issues with legacy ATE