X51 - Power board installation manual or graphic?

I just installed a new power board in my X51 R1. Went smoothly... except there's a port on the new power board that I don't recall unplugging from the old one. I'm pointing a screwdriver at it in the attached picture. I don't see any loose cables floating around, but I'm second guessing myself. Yes, I should have taken photos and paid attention when I was unplugging everything.