Old panel button switches - repair or replace?
I recently got an Kawai R-100 drum machine (it's got some of "those" sounds I like).
The problem is several of the function buttons as well as some buttons on the numeric keypad are kinda bad (seems the drum pads work fine though) - a normal press usually gives no input, if I press a bit harder / wiggle a bit they usually give input, but often they then 'glitch' and give several presses.
I have opened it up and inspected the insides of the machine, the button switches all are 4-pin through-hole pcb mounted, I tried working them with some contact spray but with no real improvement.
I tried to measure with a multimeter to find out the pin-configuration of them but I couldn't really make heads or tails of them...
Are there any 'tricks' or adjustments with switches like these to get them working better or should I try and find some kind of replacements for them?