Could you post a pic of the trace that you had to make as I would like to see what all had to be done to get it to work.
Of course I can! Fortunately the thing can be taken apart by hand without tools and it won't get messed up as a result. Here is the underside of the board:
The two pins that the arrows are pointing to seemed connected. I have no idea why they would be.
I cut them and the Arcade Card Pro worked perfectly, and so far every other PC Engine
game that I've tried still works as well. Before you go slicin', make sure it doesn't work for you first!