Ahh, yes the silly safety 2.1mm jack. I have a U1620A with no original supply myself. There are some regular 2.1mm barrel jacks that still fit. Another option is to find a reasonably narrow/long one and/or shave the outside down.
I'd like an original plug myself if someone happens to have a source.
I wouldn't mess with the scope itself, as I said it is easy enough to shave a plug down so it fits, much nicer vs hacking up the scope.