Well,

What are the sings of a bad motor versus bad 3-in-1? If a motor is bad wont it just plain not function, especially if the brushings are shot?

And could lack of sufficient lift be an indication of a bad 3-in-1? I know anything is theoretically possible here, i'm just what asking about what is most likey. I figure a blown out 3-in-1 would lead to no current at all being applied to the motor. Is it common to see 3-in-1's go bad where it cannot provide sufficient current to the main motor?

Lastsly, I have eight brand new 370 motors purchased for r/c trucks. Would these work as replacements in a Falcon 40? They are the identical size/shape of the stock motor that came in the heli.

Thanks!