[This happened back in February, but a new job and moving states has delayed my ability to deal with this until now. Since then, it has sat untouched in the factory packaging waiting to be addressed.]
I got a Filco Majestouch TKL on Amazon back in August of last year and in February several keys suddenly went out (not even 6 months of use). Backspace, Tab, T,Y, open bracket, closed, bracket, Caps Lock, Left Shift all seemingly arbitrarily decided to stop working. No trauma occurred to the keyboard (drops, spills, etc). As far as I can tell, it was entirely random.
Being well beyond the Amazon warranty period, I went to Filco's website but didn't turn up much with regard to warranty, using google translate. It also seems like a huge effort to ship it back to Japan and vice versa. I decided to void the warranty, break the sticker, and open it up to see if I could see anything wrong myself. I could find no visible flaws or shorts that jumped out at me. What may have caused this? Could it be a controller problem?
The cord pigtail/header looks fine as well. Plus, I would think if it was a cord issue the whole board would be dead, which is not the case. The vast majority of the keys work, and the caps lock light (one of the dead keys) even blinks on when first plugged in, but then does not respond to presses. That sounds like it would be a switch issue, but the shear amount of keys that went out, and their arbitrary placement, makes me think it's a problem with the controller or a bad trace somewhere.
I'd really like to MacGyver this back to life if at all possible...