Hallo, ich habe die Tastatur Sharkoon Skiller Mech SGK3 leider mit etwas Kaffee überschüttet - das sofortige trennen vom...

This is a very common problem with the G502 and the plastic part hitting the switch is constructed in a way that it blocks the movement before hitting the switch too deep. So the best way to fix this is to replace the switch like @isakrittl said/linked. A cheaper way is to switch the switches. For me my left button is word out and need the replacement while the other keys are still good. There are 5 Omron D2FC-F-7N build in, so what I do is to change the G9 switch to the left mouse button, as I rarely use it. While you do this make sure there is no dirt under the buttons. I had to disassemble all the top parts to clean them. You have to do this carefully and I was missing any instructions for that. Sorry for the bad language as I'm no native English speaker. And good luck to all with the repairs! Also a hint: The transparent plastic over the laser is not very firm attached - I would suggest to fix it with for example hot glue. (don't put glue in the line of the laser!) I've had this with the G502, G500s...