How to detect bad cable join when cable tester passes the tests

[velis]

...
But the actual connection likes to break down every so often.

I have these (low quality) wall jacks for RJ45. They seem OK, but I'm having issues with pretty much every one of them, so I'm guessing I'm not the problem. Ordinary cables that I clamp together usually work just fine. Anyway, the end result is that my main connection between the two WiFi routers in the house decides to take a hike every now and then. I'm also guessing that even when it's working, the connection probably doesn't reach 1Gbps, though I have not extensively tested this.

Even while connection doesn't work, my cable tester reports the cable as OK. There's a 20cm difference (longer) in measured cable length on one pair that for the other 4 pairs.

The funny thing is that the last time I was fixing this, just unplugging / replugging a cable into the wall jack fixed the problem. My guess is that the threads in the jack are either twisted (don't look like) or like to oxidise very much.

What would be the best way for me to solve this issue, except from ripping the wall plugs out and just pull the cable through the resulting hole?

 

[JackMDS]

I do not know what type of wall jacks you have, most of them are easy to replace.

http://www.monoprice.com/product?c_id=105&cp_id=10513&cs_id=1051309&p_id=5384&seq=1&format=2

 

[Fardringle]

If you know that the jacks are low quality and suspect they are a problem, replace them. (or just replace one for testing if you don't want to swap all of them out right away)

 

[Sheep221]

Pairs have varying length on tester screen because they are twisted under different angle(basically they are twisted more tightly or less tightly).
Best way is to just connect laptop to socket directly, run command such as ping google.com -t and move with the plug while it is connected to see if disconnection or packet loss occurs and when it does. Some of those RJ45 wall sockets are really poor so it might be the socket afterall.

 

[velis]

Well, the plug I have right now is this one. The same company also makes this one, which seems higher quality, but ultimately I just need one with KS keystone fixing standard (to properly insert into the frame).