There's a working link for the AN-200 service manual, in the second post on this page, by tux:
(links to )
It contains the circuit diagram of the PLG150-AN, on the last page.? That's all I've found, so far.
That forum is a good place to ask.? There's also a Downloads section there (start at the main forum page and scroll down til you see it).? There are service manuals for a lot of old Yamaha gear, but I can't see any for those cards.
I downloaded as much as I could of all the yahoo groups I was a member of, including the three Yamaha ones (YamahaDX, YamahaDXfiles and yamahablackboxes) but I can't see them in any of those.? I can't be sure I got it all, of course.
- Andy
AndyHornBlower