AM radio was (still is) one of the best tools for finding issues like this sparking motor. The real trick is to find an AM radio station that you enjoy listenin

AM radio was (still is) one of the best tools for finding issues like this sparking motor. The real trick is to find an AM radio station that you enjoy listening to every day, and when you hear interference, drop what you are doing to find the source. Engines and motors close to your server room will create disk errors and absolutely wreck any signal in unshielded wiring.