How to Identify a Power Receptacle
Looks to me to be a "163" obsolete-standard line cord.



You may want to consider removing the existing socket and hard-wiring a locale-appropriate line cord to the instrument (at your own risk) - make sure that the 'line' goes to the fused path! 

Another (perhaps safer) option would be to leave the socket in place (cutting off the wires coming from it), drilling a hole in the chassis and feeding the replacement line cord through a grommet/strain relief that's fitted in the hole.