FYI ... I've had an earth leakage breaker trip several times when connecting the power connector to the back of the teleprinter (when the machine is turned off). 

I think what is happening is, since all the pins are the same length, the active and earth sometimes connect before neutral. There is a filter block between the power connector and the switch which could give enough current to pop the earth leakage breaker.

Anyway .. connect the Amphenol connector before plugging the NEMA plug into the power point (and, when disconnecting, remove from the powerpoint before disconnecting from the teleprinter).

Michael