The normal takeoff procedure is to manually take the engines to 70% at the beginning of the roll. At 70% the "N1" button is pushed which causes the TMC to takeover the rest of the throttle control.
We had a aircraft abort takeoff because "N1" didn't engage (I don't know why they just didn't take it, but I don't fly these things. I'm assuming safety is the issue).
We tried the test above when we could find no other issues with the aircraft. It worked, got signed off, and hasn't had a problem sense.