Here is the 50/60 Hz Mod for PAL NeoGeo (AES) without the subboard (not shown at gamesx)
(http://i16.photobucket.com/albums/b14/moosmann/electronic/neogeo60.png)
http://mbrandel.vizionaires.net/?page_id=68 (http://mbrandel.vizionaires.net/?page_id=68)
To get 60hz, just cut the jumper "PAL1"
Bye Markus