We have a brand new scalextrix that was a gift to our son. we don’t have receipt to take back to retailer . since we assembled it one of the tracks just has the power constantly on. As soon as you put car on it it shoots off. The other track works fine. It’s not the car or the controller. Would be grateful if anybody has ideas what issue is and how to fix. It’s a shame as it’s brand new but may even be dangerous as the current is constantly flowing through. Thanks for all help!