Whirlpool double oven (model gbd307pdb09). For a few months, the unit's display would go dim when using the unit. At times, the display was unreadable. Today, while preheating the oven the display went totally dark and beeped a few times. After a few minutes (approximately 10) the venting fan went quiet. I reset the breaker, and turned the oven back on by pressing the appropriate buttons (note: the display was still dark). The unit cycled on and attempted to reheat. After a few moments, the unit beeped a few times and the venting fan went quiet after about 10 minutes. This cycle continued after I reset the breaker. I let the unit sit for about 30 minutes and then reset the power again. The display was visible, and showed a PF, E6 F2 error. Please advise how I can diagnose this problem. Thanks!