I just made a scan of one of my official 1st/2nd sheets, one of the blue ones from 1989. It's only slightly different from the one linked above, and doesn't say "2nd Edition" on it, but the copyright date is the same, so I'm not exactly sure where it originated.
600 dpi, digitally cleaned, PNG format line art, no JPG compression or anti-aliasing, prints beautifully.
Apparently I haven't posted anything here yet, so I need a couple more posts before I can link to it.
Edit: Looks like I can add it as an attachment, though!