Suddenly, we found that our phone registered as always off-the-hook.
After troubleshooting, I isolated the problem to a run to our kitchen
10 KOhm between red & green
0 Ohm between yellow and green
Both measurements were made with all equipment & connectors removed
from both ends.
Any idea what might have caused such a sudden fault? (all visible
parts of the wire are intact but I can't see the portion that snakes
up behind the wall)
Is it usual to have 10KOhm (vs either a full open or short) between
Why is there also a full short between yellow and green?
It seems odd to me that this would happen out-of-the-blue without any
of the wires being played with.
I had a problem similar to this also in the kitchen and fortunately the
break was close to the connection box and there was enough slack for
repair. I figured that there is always a lot of activity in the kitchen
and minor vibration of the kitchen floor after several years was enough
to break the wire.
In another situation, with my business phone line in the house, the
telephone company installer in stapling the wire around a door etc. had
put a staple through the wire but it took a year to fail. Since all
bills went the the company I was consulting for, I just had phone
company repair and it was repairman that found fault. I think they still
charged for their screw up.
you have one line or two? red and green is one pair, yellow and black
for line two.
assuming you have a modular jack on this line? try a differentr phone.
bet a cordless lives on this jack?
they are a major cause of always off hook or tied up line.
please tell us more
No just a single line (and all phones were disconnected from the line
to test it) but I was testing the other pairs too.
I ended up rewiring to use two good wires but still a bit mystified
about why it failed suddenly.
This is a common malady on those systems that had the yellow conductor
grounded at the protector and connected to the block (jack) to provide
dial light operability.
You would do well to measure resistance between each conductor and
ground. If any are grounded, remove them from the circuit. You very
likely can still create a good pair by testing (and using) two,
remaining "clean" conductors.
The cause, presumably, was a hastily inserted plug causing the grounded
pin of an RJ11 connector to bend slightly, contacting one or the other
side of the talk pair (center, two pins).
Disconnect the yellow conductor from its ground at the protector or,
better (to avoid a slight imbalance) disconnect it at the jack.
Well, this shoots-down the above if, in fact, *ALL* conductor ends were
Although rare, this is something I encountered a few times during my
career. Presumably, a nail or staple breeched the outer sheath during
construction. X-number of years of garbage trucks shaking the home as
they drove by eventually caused the staple to cross between two
conductors. This would NOT, however, cause all conductors to become
Your terminology, or my understanding of it, is falling apart at this
point. 10 kOhm is NOT a short in any sense. That's clean (open).
In any case, there should be greater than 10 kOhm between ALL conductors
and each conductor and ground. Anything less and the cable is faulted.
Another VERY good possibility is rodents in the attic or crawl space
chewing on the cable. BTDT. Good luck.
But the fault occurs with the wire disconnected on both ends...
I ended up doing this to find two good wires.
Not in this case because no connectors on either end now.
Probably this is the answer.
Well open should be infinite resistance. To me 10KOhm means that there
is something bridging across the two conductors even though both ends
are clear and free (perhaps a staple as you mentioned or something
else pinching through the wires and causing the insulation to wear away)
Once I thought I had mice... in fact, I might have had mice... and I
thought htey were eating up my electirc wires, Romex. My stove fan
didn't work. When I finall got around to fixing it, I figured out
that I had disconnected it myself when trying to fix the dining room
fixture. I think the problem there was that the rivet in the light
socket was no longer contacting the wire, but I didn't find that right
away, and waited so long for my next erfort I practically had to start
Lots of good advice from other posters. A possible cause of these symptoms
could be a lightning surge which shorted two of the wires and carbonized the
insulation enough to create the 10K ohms between the others. Regardless of
the cause, the cable is damaged and needs to be replaced. Fish a new cable
if the old one can not be pulled out.
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