I think he's saying he has no wire on the black banana jack on Fixed 1 In. He was hoping to pick up ground/common if the black banana jacks on fixed 1 and variable 1 were connected internally.
I suspect that's the problem. A good way to see if the TIU is getting power is to look into the case via the vent holes on the top when you think you are applying power. There is a red LED in there. If you never see it light, you have not successfully applied power to the unit.