Strange new PC problem

[Jarhead0331]

My main work station is powered by two separate rigs - a 12th generation i9 with a 3080ti and a 14th generation i9 with a 4080. The 3080ti is connected to 3 monitors. The 4080 is connected to a single monitor and a VR headset.  The two rigs share the main monitor and all peripherals (ie. mouse, keyboard, HOTAS, etc.) through a KVM and USB switch. More specifically, the mouse and keyboard are plugged into the KVM switch, which has two lines that plug into each computer allowing me to switch between the two rigs. The system worked flawlessly for many months until a few weeks ago.

The problem first started with the 4080. When I powered it up, it stopped detecting the mouse and keyboard on start up. I was eventually able to solve the problem by unplugging the KVM line into the 4080. Once plugged back in, the computer detected the mouse and keyboard and everything works. However, when shutting down, and rebooting, the problem started coming back with greater frequency and now its pretty steady.

This morning, I powered up the 3080ti and had the same problem! I've never had it with the 3080ti before today. The problem was solved the same way, by unplugging the KVM line from the 3080ti and plugging it back in.

Any ideas what could be causing this, or how to troubleshoot it? Its not a show stopper, but having to crawl under my desk to unplug the lines each and every time is getting to be a real pain in the ass. 

Thanks. 

[steve58]

Since the KVM and USB switch are common to both systems, I'd try swapping them out, one at a time.

[Jarhead0331]

Since the KVM and USB switch are common to both systems, I'd try swapping them out, one at a time.

You mean by trying a new switch?

KVM switches that have the audio and peripheral support I need and that support 4K are rather expensive. If there are any other troubleshooting suggestions before I incur the expense, I'd prefer to exhaust those.

I don't think the USB switch is the problem since it is the mouse and keyboard that don't get detected and which are plugged directly into the KVM. The USB switch is plugged into the KVM too, by the way, and it is connected to my HOTAS, rudder pedals, etc. I will say that the USB switch is somewhat new and perhaps that is causing a conflict!? 

[bobarossa]

One troubleshooting technique is to unplug things one at a time and see if the problem resolves.  In other words a peripheral may be malfuntioning and causing the USB switch or KVM to malfuntion. 

[Jarhead0331]

One troubleshooting technique is to unplug things one at a time and see if the problem resolves.  In other words a peripheral may be malfuntioning and causing the USB switch or KVM to malfuntion. 

Yeah...I have a strong suspicion it could be the USB switch. That is a relatively new addition to the ecosystem. I'll troubleshoot it this evening.

[W8taminute]

Assuming that nothing changed with the KVM & USB switches my first thought would be to check for any recent windows updates.  If there were any updates in the past month or so I would read the release notes.  Check for any changes to how device drivers are handled by windows.  That sort of thing. 

So other low lying fruit that you can reach for is to check all the cable connections.  Look for any signs of damage to the connectors or the cable itself.  That includes looking at the entire length of cabling to see if there is any signs of crushed or splayed cabling.  Make sure the pins inside the connector housing are not bent or broken. 

Check the ports on the KVM and USB switches as well.  Looking for signs of damage. 

[Tripoli]

  

[bobarossa]

Did you get a puppy recently?  Look for needle-like holes in the cables.

[Jarhead0331]

It's looking like the USB switch is the culprit. I disconnected it from the KVM switch and the mouse and keyboard have been working normally since on both rigs. I'll continue to test for a few days.

[ArizonaTank]

It's looking like the USB switch is the culprit. I disconnected it from the KVM switch and the mouse and keyboard have been working normally since on both rigs. I'll continue to test for a few days.

I've had a USB switch fail... Just stopped working. Surprised me because it was only about six months old. I just figured it got zapped by static or something.

[Jarhead0331]

It's looking like the USB switch is the culprit. I disconnected it from the KVM switch and the mouse and keyboard have been working normally since on both rigs. I'll continue to test for a few days.

I've had a USB switch fail... Just stopped working. Surprised me because it was only about six months old. I just figured it got zapped by static or something.

So far, mine seems to be working, its just creating a conflict with the KVM switch. Its hard to find a KVM switch that handles HD, audio and multiple USB peripheral devices. They really seem designed for basic functions. The higher end KVMs with more options get very expensive. 

[Jarhead0331]

As it turns out, it seems that the USB switch was not the problem.

After disconnecting the USB switch, the problem started again, wherein every time I turned on the computer from a dark state, the mouse and keyboard would not be detected until I unlugged the USB cable attached to the KVM switch and plugged it back in. As it turns out, my USB switch was not even connected to the KVM switch. Rather, it has USB lines running directly into each computer.

In any event, the only thing I could think of was that the KVM was, in fact, on the way out. Either that, or being several years old, perhaps newer Win11 updates created a conflict of some kind. As a result, I picked up another one that was a relatively modest price. I spent under $200 and it can support up to four PCs and three monitors with audio and three USB ports. Man alive...disconnecting the old and installing the new was a giant pain in the ass due to the location of the PCs under my desk and all the damn wires down there. The new KVM requires a ton of lines to function. I now have three PCs connected to it and for each one, it needs two HDMI cables, a display port cable, and a USB. That's 6 HDMIs, 3 displays and 3 USBs. On top of that, it needs another 2 HDMIs and a display port cable that run from each monitor to the KVM, for a grand total of 8 HDMI cables and 4 Display port cables! If I was to add a fourth PC to the echo system it would require another 2 HDMIs, another display port and another USB!!!

So far, its working great, but for one major issue. I can't get the KVM to recognize the display port cable running from the monitor into the KVM. I've tried two different cables so I'm pretty sure that is not the problem. The other thing I want to try is to maybe run the display port line to a different monitor and see if that works. I understand that the majority of KVM issues have to do with incorrect setup, so there is a big possibility the problem is on me.

Its not the end of the world because I can still just run the display port line directly to a PC and get it to function that way, but then of course switching the KVM won't provide functionality for that monitor that is not connected to it.

In any event, the hurdles we jump through...serious first world problems.