Hopefully somebody can give me pointer to save Christmas dinner. our Samsung BF3ON3T11 built in oven has developed a fault. When using the oven it will run through the pre heat cycle warming the oven but when that finishes and you switch to either top or bottom oven in fan or conventional mode the oven goes cold. on the display it alternates between the time and "pre" also you can hear the fan running. everything works fine on the grill setting. Trying to get somebody in to sort it before the Christmas break is proving difficult