Investigation of the occurrence of: No-faults-found in electronic equipment

This paper investigates the occurrence of the NNF (no fault found) failure in electronic equipment. The main types of NFF are outlined, and then the results of accessing the Loughborough University reliability database to investigate the root causes of NFF is discussed. The presence of complex components and connectors and the effect of equipment complexity and fraction-usage are examined as causes of NFF. The presence of connectors or complex components on a board and the fraction usage, and the complexity of equipment have little or no effect on the number of NFF events. No relationship was found between equipment usage or equipment complexity and NFF occurrence. The reason for such a high incidence of NFF in electronic equipment has not yet been identified, and further work into this phenomenon is required. Of course factors such as software faults and transient effects, amongst other causes, are likely to be involved