Failure Diagnosis on the LT1280

The high-density circuitry and I/O pin population of the thermal conduction module (TCM), the VLSI package used in the IBM 3081 processor models, dictates that there be a precise and cost-effective method of detecting and diagnosing TCM defects. This paper describes the challenge faced in testing the logic and random access memories of the TCM and the diagnostic approach used in the LT1280 test system for testing the TCM through its I/O pins. The generation and application of tests are discussed, and the automated multiple-defect diagnostic (AMDD) algorithm is presented in detail.