Using infrared thermography to detect age degradation in EPROM chips

Dozens of circuit cards (about 5% of the total) failed to function after a recent upgrade of the digital Flight Control Computer (DFLCC), even though all of these cards operated correctly before the modifications. The shop called for the use of the infrared camera to assist in diagnosing and repairing these cards. What the Neural Radiant Energy Detection (NREDS) found was faulty and marginal chips. Of particular interest was the presence of degraded EPROM chips on the Program Memory (PM) cards. While it is known that EPROMs have a limited life cycle (in terms of number of total recordings), the failure has been further characterized. Thermography provides a quantification of the degradation in thermal performance as the EPROMs are reused. When the heat rates exceed a given value, the EPROM chips will not accept a program. Some of the failed chips exhibited enormous heat rates. What is clear from these results is that infrared thermography can be used to identify degrading EPROM chips for replacement before failures become immanent.