I know you said you checked, but I'd recheck around the 68000 again. I've seen some cases where battery crud has leaked underneath the socket, and the entire socket needed to be replaced to get at it all.
+1 to clean & reseat the board a few times.
Also I'd be willing to test the card for you in one of my 2000's if you wanted to send it down, but as I'm in the US you'd probably be better served to find someone in Canada, instead. What with shipping and all that.
Good luck!
