This question was updated on 2020-01-23. See the updated section, below.

I have a very specific problem involving one specific desktop computer and one specific ethernet wall jack. I've already tried several different approaches to troubleshoot the issue, so please read this post carefully as I describe them.

I have a desktop computer (specs at the end of this post) connected to an ethernet wall jack in my condo. A couple of days ago, I noticed that the internet would periodically cut out for a short period of time. This was first noticeable as a loss of video quality when streaming, but also manifests as longer initial connection times when the computer is first turned on, periodic changes in the network status icon, and disconnection from online gaming.

Of course, my first approach was to try switching the ethernet cable with a different one. This did not correct the problem.

Next, I made sure that all WiFi connections in my unit, such as those on my mobile devices, were functioning normally. There are no issues with the WiFi.

Next, I tried connecting my work laptop to the same jack that the desktop machine was using. I disabled WiFi connectivity to the laptop, to prevent it from switching over, if it lost the signal. However, there were no issues with using the laptop in the same jack that the desktop machine was using.

I have a second wall jack in my home office area, so I tried taking the desktop machined over there, and plugging it in to that jack. Here's where it gets interesting. The desktop machine had no issues running from that jack. In fact, I was able to play on online game for a significant length of time, without interruption. Granted the monitor in my home office area is not HD, so the download bandwith requirements may have been lessened. However, they would still have been significant, and when plugged into the first jack, I was still getting issues, even when no user programs were active.

I've tried leaving the laptop running on the first jack and the desktop running on the second jack, to see if Windows Event Viewer picked up any disconnections, but none were received on either machine.

Finally, on the off-chance that a power fluctuation was the issue, I tried plugging the laptop into the first jack, and running power from the same power bar as the desktop computer, with the desktop machined and its peripherals (speakers, external sound amp, monitor) all running at the same time. Still, Event Viewer detected no connectivity issues with the laptop using the first jack, nor did it switch to battery power.

To sum up, this problem ONLY occurs with the desktop computer, and ONLY occurs with that one specific jack.

This puts me in something of a Catch-22. I can't bring the desktop to the store (it's still under warranty) and say something's wrong with the ethernet card because they'll point out that it works fine in another jack. I can't phone my ISP because they'll point out that the WiFi is working, as well as the first jack with a laptop and the second jack with both computers. I can't get my building to look at it because they'll point out that the jack works fine with the laptop.

Any suggestions would be appreciated. Specs follow.

UPDATE: Acting on the advice of the IT head, at work, I purchased a remote network tester (product description here, if interested: http://www.amazon.ca/gp/product/B017SM0G1U). To make a long story short, I ran a test of both jacks. For the jack that works with both computers, all eight lights lit up; for the jack that does not work with the desktop machine, Light #7 did not light up, indicating a problem.

Now that I've confirmed that there is a problem with the jack, the only issue is determining whether the issue is with the wiring in the wall, or with the wiring in the telecom box (i.e. whether I should contact the condo or the ISP). Any advice in this regard would be appreciated.

Desktop Computer

Aeon 1080 Gaming Tower, Intel Core i7-7700 3.6GHz Quad-Core, 8 GB DDR4, 1 240GB SSD and 1 1TB HDD, RealTek PCIe GbE Family Controller, Windows 10 Home 64 Bit


Lenovo ThinkPad, Intel Core i5-8250U 1.60GHz, 8 GB RAM, 256GB SSD, RealTek PCIe GbE Family Controller, Windows 10 Pro 64 Bit

  • 1
    "However, there were no issues with using the laptop in the same jack " Update the ethernet driver on the problem PC. – Moab Jan 18 at 18:06
  • @Moab Thank you for the suggestion. I updated the driver from the manufacturer's website. Unfortunately, the issue is persisting. Also, I'm not sure that a driver issue would explain why the desktop computer works with one wall jack but not the other, as both go to the same router. – J.P. Brown Jan 18 at 22:32
  • Easy solution is to buy a cheap ethernet 4 port router, connect it to the good jack, then the other PC's to the router. – Moab Jan 18 at 23:07


So, just to close this off, the condo builder sent a technician from the telecommunications company to my unit, and he determined that the jack was, in fact, defective. The jack has now been replaced, and everything seems to be working.

I think the moral of this story is, if you suspect a defective jack, procure a network tester, and test the jack. If the problem is intermittent connectivity caused by a single wire among eight, you cannot depend on a standard A/B test to diagnose the problem.

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