An expert system designed for performing troubleshooting diagnostics in manufacturing and assembly equipment is described. The components that make up the system, and their individual functions are discussed. The system is fully operational and in routine production use. Its innovative aspects are described at length. The system is generic in that it can be used for virtually all kinds of machines with rotating components. The modularity is obtained through separation of databases and knowledge bases. The system utilizes sensory data, and can serve both as a diagnostic tool and as a predictive tool. Furthermore, no "trend" or "baseline" data is needed. The paper includes our experiences in the complete development cycle of the system including development, implementation, testing and validation considerations. Results and benefits of our work are summarized.