Display dims and brightens...

Kitchenaid electric range - control panel dims, brightens and eventually the oven powers completely off followed by "PF" message. We’re not 100% sure but this seemed to happen only when the oven was being used, no problem when only using the cook top. Last time it happened it was accompanied by a loud humming noise. I checked the breaker and the voltage at the oven and that seemed to be fine. Any ideas or suggestions?