We have found one software suitable in our database for this conversion.
All kinds of Adobe PageMaker documents (including .ab65) can be exported and saved as PDF documents. However, it seems that this can be only achieved using the original software and no other. If you do not have access to old PageMaker, try to check some website with old / abandoned software to perform this conversion.
Updated: July 18, 2016
One of the first desktop publishing programs, introduced in 1985 by Aldus Corporation, initially for the then-new Apple Macintosh and in 1987 for PCs running the then-new Windows 1.0.
It was later bought by Adobe and rebranded Adobe PageMaker. The last version Adobe PageMaker 7 was released in 2001 and in 2004 the product was discontinued and slowly replaced by Adobe InDesign.