Digital clock went dark and oven and broiler will not come on. But, if oven knob is turned on to either "bake" or "broil" the clock comes on and can be reset, heater elements still do not come on and the clock goes off as soon as the oven knob is switched off. I was wondering if this is a clock replacement issue or a sign of a different problem.

Flipped breaker, no change. But based on your lead I will check lines to breaker and to the box that the oven must connect to in order to check for 2 120V lines as perhaps a connection failed. I will post what I find probably tomorrow or the next day.