Why unit is silent upon start. doesn't heat food?

If this oven had been in use for a while, you might have an intermittent magnetron. As they age, resistance builds up on some of the elements inside. Eventually they just stop oscillating, but some end up on the fence; not being able to decide to oscillate or not. They become intermittent for a while, and then eventually fail completely.

I have also seen intermittent high voltage rectifiers. They usually fail sooner, rather than later.

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Maybe. The presence of metallic material (foil, stainless steel silverware, etc.) in an operating microwave oven creates electric arcs between the foil and the inside wall of the oven. And this can destroy the electric components.

Sounds like someone tried heating something up with metal attached or possibly left a utensil, Chinese food with the metal handles or foil in the unit - throw it out and but a new unit - it's not worth it parts plus labor and it will never work right again the power scale will be off

emerson mecrowave mw81195bm clock works but I can heat anything it doesn.t work inside

If the unit operates correctly except heating the food, then the unit needs a new magnetron.

It sounds like one of the door switches has become defective, each must be disconnected on the one side and tested with a digital meter using the ohms scale.

If your microwave runs, but doesn'theat your food, verify that you have selected a cooking setting. You mayaccidentally set the timer. Test the magnetron by placing 1 cup of water in themicrowave and heating the water for three minutes. If the water doesn't heat,your magnetron is dead.

If your microwave runs, but doesn'theat your food, verify that you have selected a cooking setting. You mayaccidentally set the timer. Test the magnetron by placing 1 cup of water in themicrowave and heating the water for three minutes. If the water doesn't heat,your magnetron is dead.

If the steam is not leaking out of the microwave it is no problem. Steam is normal when you heat moist items. If it is leaking out you need to replace the door seal, but steam will not start a fire.

The most likely cause is a defective magnetron, "heats food" cost to repair will be close to a new microwave oven.