Issue with CAT5 / CAT6 cable - sporadic miswire

[dw886]

I'm running into an issue with one run at wires that's about 40' in length. It's a bundle of 2 UTP CAT6 cables, 3 UTP CAT5 cables, and 2 runs of RG6. I was using two of the CAT6 cables for an HDMI balun and it started to get flaky (losing handshake between devices, and then coming back after a few seconds), so I'm in the process of trying to figure out what is going on.

I have an Ideal VDV (http://www.amazon.com/Ideal-Multimedia-Tester-Discontinued-Manufacturer/dp/B000IBNXUK) tester tor testing data / phone / voice cabling runs. It you have no experience with this tester, it continually tests about every few seconds, showing the results on the screen.

When I clip onto any of the data cables in this run, it'll show "PASS", and then two seconds later on the next test, it'll show "Miswire", and then it'll show "Open", and then it'll go back to "Pass". Not necessarily in that order either, but basically it looks like the cable is good, and then it doesn't…

I've re-done all of the ends, I've verified the VDV tester is working correctly by using another cable (not from this run of cables).

Any thoughts into what could be doing this? I've never seen this before, and I've pulled/terminated thousands of feet of data cable…it's almost like there's some kind of interference taking place...

 

[fcwilt]

At times like this you need a 'scope to see what's on the cable.
 
I was frustrated dealing with this type of issue so one day I got something like these:
 
http://www.mcmelectronics.com/browse/Handheld-Portable-Oscilloscopes/0000001249
 
Small enough to keep in the toolbox and doubles as a meter.
 
Very happy to have it.

 

[pete_c]

Here helped a neighbour with an intermittent control issue with one zoned audio keypad which was using cat5e a few years ago. 
 
It was very random issue working most of the time.  The home was a ranch with multiple levels.  The attic space had been utilized for all of the LV cabling done during the build. (~ 2001?).  None of the cables in the attic were using hangers.  It was mostly just draped over support beams from what I could see.  We physically traced the one control pad cat5e cable the source (kind of a PITA) to where it went and found it sort of wedged between two cross beams of roof support in the attic and it pinched it compressing it totally flat.  Just moving the cable created the intermittent issue with the audio control panel.  We just replaced the entire run of cable.

 

[dw886]

Anyone have a good simple reference on how to use a scope to narrow this down?  I had a co-worker ask a buddy that works in the cabling industry, and he said it was likely a cable kink.  He also said there's tools available that would help to narrow it down to the exact location in the wire.  I'm not sure if he was referring to a scope or something else...
 
I'm hoping that I don't have to try to re-pull the wire, the ceiling in this room has loose-fill insulation to help deaden the sound, which means that there's cardboard stapled on top of the outer walls of the room to contain the loose fill, so it's not exactly going to be easy without making holes, even though I can see the space from a (fairly close) furnace room that has no ceiling...

 

[pete_c]

Personally didn't enjoy the attic visit and almost did trip up there as there was only wooden beams to walk on with loose-fill insulation. 
 
I did utilize a toner to find the wire in the attic. (apologies as I stated no tools earlier).
 
Then just followed the to and from of the cable with a large lamp as there was no lighting up there.

 

[fcwilt]

Anyone have a good simple reference on how to use a scope to narrow this down?  I had a co-worker ask a buddy that works in the cabling industry, and he said it was likely a cable kink.  He also said there's tools available that would help to narrow it down to the exact location in the wire.  I'm not sure if he was referring to a scope or something else...
 
I'm hoping that I don't have to try to re-pull the wire, the ceiling in this room has loose-fill insulation to help deaden the sound, which means that there's cardboard stapled on top of the outer walls of the room to contain the loose fill, so it's not exactly going to be easy without making holes, even though I can see the space from a (fairly close) furnace room that has no ceiling...

 
There are a number of tools out there that can help with this can of problem.
 
Check out Flukes' MicroScanner2 - I think it might do the job BUT read the manual first - it might not handle all cases of this type.
 
I know their Cable IQ would do it but its a $1000, give or take a few $100.