There will be two flexible printed circuit (FPC) cables.

One of the FPC cables is wide and yellow in color, which corresponds to the screen cable. The other FPC cable is narrow and blue in color, which is connected to the control switch panel.

You can only disconnect the narrow blue FPC cable. Unlike the screen cable, the connector for the control switch panel is loosely connected without any locking mechanism. Therefore, the issue is likely caused by frequent use, which has resulted in a loose connection over time.

Before reinserting the cable, I recommend cleaning the golden contacts (which are actually black in color).