Just received my centipede set and neither unit functioned properly right out of the box. MY layout is DC . As stated in the manual, around 7 volts the headlight comes on and the sounds begin. Then the units shut off and the cycle starts again. Any further increase in voltage does not change the situation. After a half hour of fiddling around, finally the lead unit ran thru the sounds and actually started to move, only to shut off again a few feet down the track. The "B" unit continues to turn on/off. Any thoughts or should I just return them to BLI?