I have a couple of questions concerning a small dc motor that operates a moving display track. It uses a 15 volt 400ma adapter which checks out fine. The motor powers a sliding arm that reverses when it reaches the end of the run and vice versa. What I am having trouble with is keeping the motor running. After a minute or so the motor quits, when I disconnect the motor and wait a minute or so and re-connect it, it runs again for another 15 seconds. I went out and purchased 2 new similar motors and they do the same thing. If I hook the motor up directly to the ac adapter the motor will run with no problems. The adapter powers a little circuit board that houses the electronics for the reversing switch, from here the wires go to the motor. Is the problem in the switch or board? Are there motor problems? Thanks in advance for the help.