No longer heating after a power outage

We have a Litton Microwave model 1880, that is also a "range" which is connected to the oven and the stove. My grandparents got it in the 1980's, but has worked well up until a week ago, the morning after a power outage. The problem is that it appears to be heating the food, but it's not. We've flipped a couple of power switches on and off in the garage, but we're not sure that we got the right ones, since there's not one specifically labeled "kitchen" or "microwave/oven/stove." My parents and I work, so getting a repair man will be a chore to arrange. Does anyone think they know the problem? Or, preferably, the solution?