JDM-040 options/share button vias for arcade stick

[JohnMadden]

TL;DR how would you solder arcade buttons to options and share buttons respectively?
Looking to build an arcade stick using a jdm-040 as the pcb because cheap with reliable latency. Everything but options, share, touchbar, L3 and R3 can be have buttons soldered on by scraping away at the top layer of whether the daughter board connects to the main board, shown to work with earlier models here (https://youtu.be/AklutmWoFXw).

With the size of the connector pins on the L3, R3 and touchbar pushbuttons I could solder wires onto those points fairly easily, however the problem comes with the option and share buttons.

The buttons/vias seem far too small to reliably desolder/solder without damaging the board in some way. Further l can't find any clear path from the visible layers of the pcb to these buttons (The main thread showing jdm-040 pcb vias doesn't seem to know either), so I have no clue which vias connect to options or share. Ideally I'd like to have all 14 buttons and the d pad usable so would really appreciate if someone knows whether there's any practical way to solder an arcade button to mimic/replace the options and share buttons.

Also if someone knows the specific voltages to neutralise triggers that would also be super helpful as the board has drifting analog sticks.

Thanks.

[RDC]

Fastest and easiest way to get to the Options and Share buttons are to just remove them and use the pads that are there. Top 2 are Ground, bottom 2 are the button line. If you have a hot air setup that will do the trick, but you can also just drown the whole switch in solder and gently, do not pry or push, just gently move the iron around so that all 4 leads of it will get heated and then it will 'wipe' right off the board and you'll have a couple of easy to solder to pads for each one. It destroys the switch in the process, but you're not using it anyway. Also, do not have the heat cranked up to the max on the iron as that will just cause damage as well as removing the switch.


For the L2 and R2, put a 10k Resistor from L2 to 3.2v, then another 10k from R2 to 3.2v and the L2/R2 will stay unpulled. If you want to use the L2/R2 on new buttons, then use L2 and 2L for the new L2 button, then R2 and 2R for the new R2 button.




L1, R1, L3 and R3 all use 3.2v as the common, every other button uses Ground.