I believe the pin-out is as per the attached image. However, I suggest you proceed with great care. Personally, I spliced the original ribbon, and carefully soldered standard motherboard connectors to the appropriate leads. I then started the computer, and one by one, tested each item, ensuring that every LED, switch, socket, etc did not cause a hardware fault.
I found that one of the USB ports had blown on my control board. I suspect this was the original cause of my failed Dell motherboard. I still wonder to this day, whether in fact the Dell motherboard was actually fine, but the blown USB port was faulting out the Dell motherboard.
If you need any further clarification, or photos of the control board for your comparison's, then don't hesitate to ask.
Good luck