I have an Elba double oven cooker but the large main oven has stopped working while the smaller oven still works. There is no timer on my cooker so it cannot be to do with that. There appears to be no power to the light, fan or heating element of the main oven but the light and heating element on the small oven do work. There is only one power cable entering the back of the cooker. Can anyone suggest what the problem might be.