Double Ovens

Had GE Service call paid $86.00 . GE said it need a control
smart board which is part #wb36k5241 and is no longer available
but i still pay the bill, they can’t supply the part for there oven
whatever???

My question is the oven works except the convection bake does not work
on the top oven and that is what i use.

Do you think this is the problem with the oven?