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.
A ground test of the A/T's can only be done with the engines running. On the FMC, go to the takeoff page. Put 60 in the scratch pad and then move that into the thrust setting with the (left) side button. That will give you a max de-rate for the day. Flaps at 5, then push the N1 button on the MCP. The autopilot does not have to be engaged and the EEC's can be on or off. The N1 bug select on the EICAS panel has to be pushed down (not in manual mode). Only the takeoff mode will work in the TMC.