Key not working (simultaneously permanently on and not on at all)

Jesse helped me out last time by helping replace the A key on my keyboard. I’m now seeing this again on my I key. It was showing chatter, so I used the techniques suggested in this thread: What to do if your keyboard seems to duplicate keystrokes or a key stops working

After performing the alcohol steps, when I replugged in my keyboard the I key was permanently in a pressed state. I.e. pushing the key didn’t do anything and switching to the StalkerEffect shows the I key as permanently lit up. If I plug it into my computer it will usually not register any I presses, though sometimes it just registers permanent I presses (infinite key repeat).

The solution last time was to replace the A keyswitch, so I’d like to do the same with my I keyswitch.

A few questions before I do:

  1. Are there any other diagnostics I can do before resorting to the soldering iron?
  2. Does anyone know a good place to purchase a replacement Matias Quiet Click keyswitch (I only need one - or a few to have spares, but not a whole bunch)? @jesse if you have any in-stock could I purchase a few off you directly (for local pickup)?

Thanks in advance!