This is a free software (for the reader version only). Some love it, some hate it. Not sure if .pdb is supported, but worth a try. I needed to open a .bin file right after I got my Mac, did a "Google" to find it, downloaded and installed and did what I needed it to.
The dumbest key on these keyboards has to be the "Caps Lock". Should be forever removed. Please refrain from its use as it is considered YELLING. Just a courtesy explanation.