@techb31 this "there is still no backlight on the original display." would mean that you have a bad backlight in the panel. Of course, you made sure that the display and the computer that you tested it on, are compatible. It is not enough to assume that just because they have the same connector, that the wiring is identical. Have you checked to see if your can see your desktop etc. if you shine a flashlight beam at an angle against your display? Try that in a darkened room and see what you get.
I suggest that you post some good pictures of your motherboard with your Question. then a separate one of the display connector. Let's see what it looks like. It is possible that this is a connector issue, a backlight power issue (blown fuse etc.) or a bad backlight driver issue.