1, poor contact, look at the inside of the joints loose no . Including the tin point. And when you close the door. Is not closed in place. Here sometimes also appear loose. In addition, the fuse should be twisted tight.

2, the keyboard input circuit or single-chip microcomputer input port is faulty. The microwave oven light touch membrane switch is a 4 × 6 matrix switch, under normal circumstances, not key, rows and columns between the 10 lines are not mutually accessible, when a key is pressed, the key corresponding to the rows and columns of the two lines should be connected. Such as pressing the cooking key, ① and ⑦ two lines should be connected. Key malfunction reasons are: poor light touch switch; light touch switch and connector wires loose; transistors, resistors and printed lines welded cracked, disconnected, etc.. After checking the function of the light touch switch is normal, switch wiring and peripheral components are not found abnormal. Judgment for the microcontroller damage.

3, if only individual button failure, embedded in the internal micro-button aging failure, can be replaced, the internal computer board failure, the entire board replaced.