I don't have a lot of experience with soldering, but I can manage small repairs and I regularly watch TronicsFix's repairing videos (like this one for the same issue I have). Quite lucky, right?!
So my Steam Deck had a little accident and fell off the table on its right shoulder bumper (R1). Unfortunately, the button behind the bumper (pictured here in the ifixit tutorial) took all the force of the impact and got squashed, pushed backwards. After playing a bit I noticed how R1 was barely registering inputs, so I decided to disassemble the Deck and have a look. The button looked OK, but it was bent backwards (reason why it didn't work since the bumper was barely pressing it), so I decided to push it to its original position and felt a crack...
On a closer inspection I noticed that all three pins were no longer soldered:
In order to re-solder the button, I have disassembled the button board but while doing so, I noticed that the middle pin fell off completely:
I thought that was OK, I can order new replacement buttons from AliExpress and replace it easily, but while inspecting the board I saw that the solder pad of pin B is missing completely.
I tested with a multimeter for continuity between pin A and pin C, A + ground, C + ground, all good, I get the beeping. But I get no beep when I test pin B against anything else, so I think the solder pad is gone, together with the missing button's middle pin. Also, the color of the pad of pin B is very close to the board color (brown?), highlighted by the orange arrows. I see no copper there.
Is there any solution to solder the replacement 3-pin button, even with that missing solder pad? As you can see in the picture above, there is a circle below it, possibly a trace there. Also visible on the back of the board:
On the back of the board, I tested for continuity and I can get a beep when testing against the white two dots in the red circles and the ground. Could there be some kind of a resistor there?