Hello all, I am new to the forum, my apologies if this is posted in the wrong location, or if my question has already been answered (I am unable to find it on the site). I am in the process of restoring a fairly pristine IBM model F XT keyboard. It is not functioning (I'm using the appropriate converter, tracings and cable are fine), and I suspect there is a faulty component on the controller PCB. I am not skilled in identifying these vintage components, and am hoping someone can help me out, because I suspect I have found the problem (although it's likely that I'm just ignorant!). I have identified and successfully tested the other components, it's just this one that has me confused. Please see the attached image.
Description: A red, plastic, cylindrical component with the following numerical markings:
123
85 01
492
402
