Hi John, thank you again for offering your insight. When I shine a flashlight into the rear coupler a see silver cylinder that I presume is the coupler coil - using the paperclip to give that a firm push open the coupler. While the coupler is technically "open" it seems it isn't open all the way. I am not sure how to describe it, but you know how the couplers have that internal portion that slides out when the coupler opens, that's attached to the opening component? That internal sliding piece won't come out all the way on the rear coupler.