First post, by kevmif
Hi all. Hoping for some help repairing a 486 board.
It is one of these: https://theretroweb.com/motherboards/s/suk-ju … -3vls#downloads (well very similar, looks like an earlier revision).
The traces to the keyboard controller for clock, data and ground are destroyed. 5v is fine according to the multimeter. No other apparent damage besides a spot just below the battery patched with some silver paste. Board does indeed POST.
I plan to run patch wires from the keyboard port to points L3 and L4 (top right of image) as attempting to repair the traces is beyond my skills.
Point L2, which I am reasonably sure is ground based on a continuity test had one of those black components which I removed to assess the traces better (same as L3 and L4).
My question is, what are these components and why is one necessary for a connection to GND?
Does that component have polarity or can I reinsert it any way? The black bit seems to move freely on the wire - is this normal or did I break it de-soldering it?
Thanks