Oven takes longer time to heat up. On the control panel the fan blowing indicator does not come on at once. It takes time and if it does, it stays vertical instead of spinning. It sow FF on the control panel.
You will want to check the voltage at the control board for the convection fan motor. On the control board there is a 15 pin connector. You will check from pin 7 purple/red to pin 5 white for 120 vac when the unit is set for convection bake. If there is 120 vac at this point then you will need a new fan motor and if there is no voltage then the control board is faulty.