Following a major outage, high LP hood vibration was discovered which was not present beforehand.  This case covers a thorough approach to troubleshooting and proposing a solution to mitigate a Steam Turbine Generator LP Hood resonance issue.  The testing technologies used were Modal Impact testing, Operational Deflection Shapes (ODS), Motion Amplification, and Finite Element Analysis (FEA) to design a Dynamic Vibration Absorber (DVA) system to move the hood’s natural frequency away from the rotor’s synchronous forcing frequency at steady state operation (60 Hz).  A DVA can be a cost effective and less intrusive option compared to an LP Hood structural redesign and mechanical implementation.