How to replace push button panasonic CT579SBPQ

your door switch could be faulty

You have to remove the outer cover, the plastic lift levers are behind the door open button / lever. Caution!, panasonic discontinued a lot of those and getting a replacement part can be hard at times. Dont waste your time trying to glue it. After watching people try to glue or epoxy those cheap plastic parts for so many years. I have to warn folks to not waste your time trying. .It will not hold!!!! Look online and try to find a replacement part somewhere. It will be one of two parts. the door open button you push, or the door open lever that the front button pushes against. If you unplug the unit and remove the outer cover simply look behind the front control panel and when you push the button to open the door you will see where it is supposed to lift to open the door. The broke part is your problem, may be a piece laying in the bottom.

have you pressed the stop button twice when the door is closed to exit the program set for cooking

The door switch is adjustable. one or more need adjusting to solve the problem

One of the door switches is malfunctioning and must be replaced to resolve the issue.

I would say adjustment or faulty door switches.

The microwave oven needs to be replaced, the magnetron is the most likely problem, there is also a high voltage transformer, capacitor, and diode that are potential issues. But by your description it sounds like more than one part is involved.

control panel is hung up - replace panel and keypad.

It is possible that the magnatron is bad but hard to say on a no heat problem without checking all components. A lot of model give 5-7 yr warranty on that part.

if electronic control, one of two things come to mind. 1)your toutch pad is defective.replace it. 2)you electronic board has a leaky component.not very likly though. believe it or not, ive seen it start before by itself then i noticed a large quantity of bugs inside the glass which i realised triggered the microwave 0ff.