If you are looking at the same one I was looking at bundled with the 404 sig's. Those one's don't have a switch for 117,100, 240v operations the transformer inside is only 100v but I recall remembering KG and spritzer posting a picture while ago that some T1S do have a universal voltage bandai tranny in the circuit hard wired for only 100v with no voltage switch at the back but you can rewire it internally. I could be wrong.
All T1's have a voltage switch inside the amps except the very early ones. Just remove the bottom cover to access it.