[Jukebox-list] Re: Latch Solenoid Buzz, Record Speed, Scanning Pause, Glass polish

[Jeff Dieterle]

AC coils have a small shading coil which induces current flow 90dg out of
phase with the line current. This keeps a small amount of holding current
flowing as the line current passes through zero each cycle. 
Sometimes the shading coil is a small c-shaped clip around the main coil
frame and these can fall off. The result is coil hum.