F2 normally indicates an over-temp problem. Usually the oven sensor or sometimes the control board. Most, but not all, sensors measure approx 1100 ohms at room temperature. I'm not certain about yours since I can't find any service info on it. At any rate, the power supply filter could be the cause of your noise. A failed power supply filter capacitor can cause the the control board to do odd things as well. Try replacing the power supply filter capacitors first.