Quote Originally Posted by ~Barn~ View Post
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Okay gotcha; make sense.

The part that I need soldered back onto the board is a relatively tiny diode/transistor/whatever, that performs the "click-to-unlock" on the key fob. I have it all taken apart already, and I can see where the click-to-lock transistor is still attached, but this other came loose from the board.

They're of course right under the buttons themselves when reassembled, and I think this may work - to just reattach it - because the the small transistor still clicks when I press it, but because it is no longer attached to the board, well.... Yeah.
As long as the pads didn't get pulled off when it came loose, it should be a pretty easy fix. Let me know if you don't get something figured out, we use down to 0201 parts where I work. Size reference, here is a 0402 (roughly double the size) on a dime:
https://commons.wikimedia.org/wiki/F...Femtoduino.jpg

JB Weld (or similar) isn't conductive, so probably won't fix this issue.