The leads for the PH163 type connector are only really available as new-old-stock or used, Sphere still have one in stock under the HP tab as "HP old style power cord"
https://www.sphere.bc.ca/type/hp/ , they turn up on feeBay occasionally, but easier to find over in the US.
There is also some 3DP thing on the web too, I don't like the connector sockets chosen for that.
I'm not a fan of the IEC C5, C6 connectors either, they are often very poor quality and current rating is only 2.5A, which could be an issue for those in the US.
David