or perhaps its me thats broken?

Found the trang teleporter in lower M.B. However it won't let me use it, says a specific item is needed. help/spoil needed! TIA

You can always use the teleporter...just that the destination of the teleporter will be rather randomised between the 4 possible destinations.

Spoiler!!!
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There should be some red & yellow wires found after you drop from the catapult into the courtyard. (near the dead T'Rang and the T'Rang arm)

Don't recall exactly where, but somewhere in MB or lower MB you'll find some colored wires/cables lying around. That's what you need to fix it. Just keep exploring... or maybe somebody else here can give you the exact location.