An attempt to categorize the various types of line sockets found on older tek scopes
3 pin Edison (recessed)
3 pin Edison (proud)
Found on a majority of the 500 series scopes
2 pin (recessed)
Found on older, non-plugin scopes, such as the 514. Pin spacing is standard 1/2". Chassis cutout is 1.25", Chassis mount hole spacing is 1.5" Is the metal ring on the inside of the socket part of the ground connection, as found on some multi-phase twist-lock connectors?