I have a 20 year old Maytag that is showing F2 . As soon as the oven is plugged in, the top oven element comes on automatically and the F2 flashes and beeps after it heats up. The bottom element does not come on and I could not find any breaks or bad spots on it (bottom element replaced couple years ago). I tested the temperature sensor and got 1080 resistance. How can I figure what it needs? Thanks.