Hello, you asked how to use the old computer board microwave oven before it started working. Most mechanical microwave ovens only have two knobs, one is to control the time, and the other is to control the direct rotation of firepower.

Generally, press the microwave first, then select the required time, and then press the start button after adjustment (if it is mechanical, adjust the microwave firepower and directly adjust the time knob, and it will start working! It will stop by itself then.