[ms660]

The metal volume control enclosure/body on the pot was normally electrically connected to the chassis due to the way most pots are mechanically constructed and secured to the chassis, the metal body was often used as a connection point for other components or wires that needed a return to chassis connection, those connections are not normally depicted in schematics. Its possible that there might not have been anything connected to the pots metal body originally and that it has just been used as a convenient point to connect the -ve ends of C27 and C29 to, having said that, looking at the photo that short bare link wire connected to the pots body does seem to have an original look to it.

The tubular capacitor from the chassis to the mains earth tag would have been fitted so that from an RF signal point of view the chassis would be earthed if a 3 core mains lead was fitted to the IEC plug, an automatic isolated earth connection to chassis if you like, it would be to save running a separate "real earth" wire to the receivers "real earth" connection socket on the receiver, which is also isolated from the chassis by C3, if you decide to retain C3 then it should be replaced by a Y Class type only.

Lawrence.