Alpha R2 with Graphics Amplifier no signal on TV

I just got a new Alienware Graphics Amplifier to my 3 year old Alienware Alpha R2 (6400T CPU/8 GB RAM).

I inserted a Nvidia 2070 Super (Zotac) into the Amplifier, it fits nicely. I connected power, HDMI cable to my TV and the graphics cable to the Amplifier. But when I turn it on the TV just shows "no signal". When I remove the connection and plug it back in the Alpha itself the TV display works fine.

When the AGA is connected it shows the white status light, which seems to be a signal of a good connection.

Also I can login blindly to my Alpha and shutdown the machine using Alt-F4. Obviously there is not a lot more that I can do as I do not have a picture.