eighties retro

I don't have any of the cars you mention above but I do have 2 cars that did stop working and upon checking the motor it was still good what it was was the capacitor or resistor that is connected to the wires that go to the pick ups, thats my experience I have had, the issue with 2 cars both cars came with my original set others I have bought seperatley and used more are still good maybe the cars they put with the sets are not as good as the ones you buy seperatley, I cut the resistor/capacitor out reconected the wires by soldering them and all good a bit fiddley but it works.