Ever had that experience where you didn’t change anything (that you knew) and yet some piece of equipment started behaving unexpectedly? Well here’s my story for today.
Over the last few years Microsoft has mucked about with Windows to fix issues, in particular networking issues related to SMB 1.0 and the EternalBlue issue ( https://en.wikipedia.org/wiki/EternalBlue ), and I have had some connectivity issues. At one point, in an attempt to solve these issues, I rushed out to buy a low cost batch of hardware to throw together a machine to be a network server. (Running Proxmox for those curious.) Although I was in a hurry, the machine went together pretty well, and worked for what I needed it for at the time.
Eventually the machine’s purpose became redundant, and I decommissioned it. It was working fine when I powered it off. I then carried it downstairs for temporary storage because I needed the room clear for temporary [human] guests. One thing led to another, and it was left out of use for longer than intended, probably about 4 months.
Today was the day to fetch the machine, and do a BIOS upgrade to install the newer AGESA (it’s an AMD 2700X CPU), and then reformat it and install it for its next life. I went down, retrieved it from under the eventual other pile of networking gear that I had piled on it, and carried it upstairs. I hooked it up, and powered it on… the lights came on, but nobody was home. I couldn’t get any video display at all.
What the heck could have happened to this poor machine?? I scratched my head for a bit while trying to guess what diagnostic step to take. After numerous power cycles, and rechecking and reseating all cables, still no luck. I resolved to open the beast up and see if I could any loose cables or anything else obvious. I didn’t see anything obvious inside the machine. Time to check for the inobvious…
After much poking and prodding I finally saw something I didn’t like. On the back of a standard computer case there is a cut out for what is known as the IO shield. This is a standardized rectangular shape and the IO shield usually comes with each motherboard because it is unique to the layout of the connectors of the motherboard. On this machine, I recall struggling a bit to fit the motherboard to the IO shield while being in a hurry when I assembled it. Tolerances are tight and it’s not unusual for there to be some difficulty doing this, so it didn’t register any alarm at the time.
So here’s what I think happened. There is a grounding tab on the IO shield that is meant to sit on top of the connector housing a pair of USB ports. I think that tab actually sat outside the case and nearly inside the USB connector. This would have been a consequence of my struggle to make it fit. Somehow, at the time, and for the weeks while I used the machine, it seemingly didn’t pose an issue. (I wasn’t using those USB ports for anything, so I wouldn’t have had the opportunity to notice this problem from trying to insert something into the port.) I suspect when I decommissioned the machine and carried it downstairs, the case motion cause the whole case to flex a little bit (as I previously stated it was a cheap build so it’s a cheap case, so not as rigid as I might otherwise like.) The flexing must have worked the tab into the port so that it came in contact with the pins, causing a short. Of course, since I didn’t set the machine up for use after I took it downstairs, I wouldn’t detect the problem. The problem didn’t surface until I brought it back up today to try and work on it.
If this whole story has any moral, it’s simply that you can have what appears to be a perfectly working system suddenly go wrong for reasons that can be really difficult to detect. Loose connections and connectors, a little wiggle or flex, can sometimes expose a fault no one could have predicted. It can be easy to think “but I didn’t do anything” when the cause and effect are really hard to connect to each other.
The resolution to this particular PC is that once I got it booting, I upgraded the BIOS and it is functioning well. There don’t seem to be any lasting effects to the temporary problems it suffered.