What should I do if the keys of the PCB membrane keypads fail

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This phenomenon is generally due to dirt on the circuit board or conductive plastic, or because beverages, water and other things flow into the PCB membrane keypads, so that the two cannot be connected normally. It is also possible that some keys cannot be used due to a breakpoint on the circuit board in the PCB membrane keypads.​​
The steps for cleaning the dirt are as follows:
(1) Disassemble the PCB membrane keypads. Note that when opening the keyboard, the button side (that is, the side we operate) must be down, and the circuit board must be up, otherwise the conductive plastic on each button will fall off one after another, which will bring trouble to your repair.​​
(2) Open the circuit board. The circuit board is generally made of soft plastic film, with button cables engraved on it. Gently scrub the circuit board twice with alcohol cotton with a concentration of more than 97%. Take care of the circuit of the button failure part several times.​​
(3) Check the conductive plastic of the malfunctioning part of the PCB membrane keypads. If there is a lot of dirt on it, use alcohol to scrub it as well. Assuming that the conductive plastic is damaged, it is recommended to replace the conductive plastic on the unused keys with the damaged part. Although this measure cannot make the keyboard perform all functions, at least it can prolong the life of the commonly used keys.​​
(4) Remove the dirt in the inner corners of the PCB membrane keypads. The tools can be brushes, small brushes, etc., but pay attention to the gentle action.​​
(5) Check whether the welding module has virtual welding or desoldering. If you can use an electric soldering iron, you can carry out repair welding work. Of course, this step is only applicable to friends who can use soldering irons, but those who don't know how to use them, please skip this step.​​
(6) Install the PCB membrane keypads. One thing to note here is that you must wait for the alcohol to evaporate before proceeding.

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