Why does my screen not light up?

If you hold a flashlight at an angle to the screen, can you see faint images? If so, the problem lies in the inverter. The good news is the Titaniums have the inverter in the body (as opposed to in the display, which is a PAIN to take apart). Check the connections and replace parts as needed.

If there is no images, you may need a new display assembly. If this doesn't solve the problem, all signs point to Logic board.

iFixit has guides for accessing these components, and they sell replacement parts.

Good luck!