RidgeWalker. I also have a MRC Track ll. Mine is a dual control with two cab controls. There is two screw attachment for each cab control and between them is the AC terminals. As long as you have the two wires connected to the same cab control it should work, "unless" you have a short in the track wireing someplace. If you don't have a volt ohm meter, get one at Radio Shack. They have very cheap one's which would do just fine. Be sure the wires a "NOT" connected to the MRC. With no engines on the track check the resistance between the to lead wires. If the meter needle jumps way over, you have a short in the wireing someplace. Also put the meter leads across the tracks and see what happens. It should jump way over there also.
If the meter needle does not jump over, then it is your MRC.
If the short is in the wireing someplace, go about half way between the ends of the buss lines and cut the wires. Then check each side to determine which half has the short. You can go from there and work down or up the wires