| Author |
Message |
Tekkie®
Guest
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 Posted:
Fri Jul 08, 2005 12:20 am Post subject:
Which end is bad of cable |
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Hi everyone, had to make some telephone cables up today. Crimped the ends on and tested
with simple tester I have and one conductor was open. Inspected ends - both looked good,
fully inserted, etc. Picked an end and redid it; same problem, same conductor open.
Redid other end and retested - same problem again. Redid both ends again and same
problem. I only needed the the center pair so I used it as I was running out of time and
patience. This is not rocket science but I would like to know how to find out which end
is bad. Or maybe the conductor is open somewhere... Is there a tester of some kind other
than a TDR that would tell?
--
Tekkie |
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James Knott
Guest
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| Posted:
Fri Jul 08, 2005 6:22 am Post subject:
Re: Which end is bad of cable |
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Tekkie® wrote:
| Quote: | Hi everyone, had to make some telephone cables up today. Crimped the ends
on and tested
with simple tester I have and one conductor was open. Inspected ends -
both looked good, fully inserted, etc. Picked an end and redid it; same
problem, same conductor open.
Redid other end and retested - same problem again. Redid both ends again
and same
problem. I only needed the the center pair so I used it as I was running
out of time and
patience. This is not rocket science but I would like to know how to find
out which end
is bad. Or maybe the conductor is open somewhere... Is there a tester of
some kind other than a TDR that would tell?
|
None that I'm aware of, though you may be able to set up something, using a
'scope and pulse generator. There's another technique, called a "Varley
test" which used resistance differential to find shorts and the old line
board swing test, to find opens, but you'd generally a lot more cable than
you've got, to make such a measurement. Even a TDR would be dicey on such
a short cable.
Given the cost of materials vs your time, if the fault isn't obvious, don't
waste your time on it. |
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Tekkie®
Guest
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| Posted:
Fri Jul 08, 2005 6:48 am Post subject:
Re: Which end is bad of cable |
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James Knott posted for all of us...
I don't top post - see either inline or at bottom.
| Quote: | Tekkie® wrote:
Hi everyone, had to make some telephone cables up today. Crimped the ends
on and tested
with simple tester I have and one conductor was open. Inspected ends -
both looked good, fully inserted, etc. Picked an end and redid it; same
problem, same conductor open.
Redid other end and retested - same problem again. Redid both ends again
and same
problem. I only needed the the center pair so I used it as I was running
out of time and
patience. This is not rocket science but I would like to know how to find
out which end
is bad. Or maybe the conductor is open somewhere... Is there a tester of
some kind other than a TDR that would tell?
None that I'm aware of, though you may be able to set up something, using a
'scope and pulse generator. There's another technique, called a "Varley
test" which used resistance differential to find shorts and the old line
board swing test, to find opens, but you'd generally a lot more cable than
you've got, to make such a measurement. Even a TDR would be dicey on such
a short cable.
Given the cost of materials vs your time, if the fault isn't obvious, don't
waste your time on it.
Thanks! At least I only feel stupid now vs actually being it. (But give me a chance.) |
--
Tekkie |
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Ed Nielsen
Guest
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| Posted:
Fri Jul 08, 2005 8:20 am Post subject:
Re: Which end is bad of cable |
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Tekkie® wrote:
| Quote: | Hi everyone, had to make some telephone cables up today. Crimped the ends on and tested
with simple tester I have and one conductor was open. Inspected ends - both looked good,
fully inserted, etc. Picked an end and redid it; same problem, same conductor open.
Redid other end and retested - same problem again. Redid both ends again and same
problem. I only needed the the center pair so I used it as I was running out of time and
patience. This is not rocket science but I would like to know how to find out which end
is bad. Or maybe the conductor is open somewhere... Is there a tester of some kind other
than a TDR that would tell?
Sounds more like a tester or adapter problem than a cable problem. I |
went through the same thing several years ago. Drove me nuts until I
figured out that I had a broken pin on my adapter. Replaced the adapter
and everything was fine -- including the cables that had tested bad.
CIAO!
Ed N. |
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Tekkie®
Guest
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| Posted:
Mon Jul 11, 2005 7:07 am Post subject:
Re: Which end is bad of cable |
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|
Ed Nielsen posted for all of us...
I don't top post - see either inline or at bottom.
| Quote: | Tekkie® wrote:
Hi everyone, had to make some telephone cables up today. Crimped the ends on and tested
with simple tester I have and one conductor was open. Inspected ends - both looked good,
fully inserted, etc. Picked an end and redid it; same problem, same conductor open.
Redid other end and retested - same problem again. Redid both ends again and same
problem. I only needed the the center pair so I used it as I was running out of time and
patience. This is not rocket science but I would like to know how to find out which end
is bad. Or maybe the conductor is open somewhere... Is there a tester of some kind other
than a TDR that would tell?
Sounds more like a tester or adapter problem than a cable problem. I
went through the same thing several years ago. Drove me nuts until I
figured out that I had a broken pin on my adapter. Replaced the adapter
and everything was fine -- including the cables that had tested bad.
CIAO!
Ed N.
Thanks Ed, that will be my next step. |
--
Tekkie |
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Michael Quinlan
Guest
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| Posted:
Mon Jul 11, 2005 8:10 am Post subject:
Re: Which end is bad of cable |
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I have an Ideal Linkmaster Pro XL that will tell you the length of the
cable, or you can select individual pairs for length measurement. It
measures length using capacitance, not TDR. For OPENS, I measure the
length of the offending pair. If the length is ZERO, then the problem
is at (or close to) the near end. If I get a length reading greater
than zero at each end, then the problem is in the middle somewhere.
This approach only works for OPENS though. For SHORTS you still need
a TDR.
I think you could use the same approach with any tester that measures
using capacitance, as long as you can measure a selected pair.
Another way to check would be to plug each end of the cable into a
modular adapter, and then use a continutiy checker on each conductor. |
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James Knott
Guest
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| Posted:
Mon Jul 11, 2005 2:48 pm Post subject:
Re: Which end is bad of cable |
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Tekkie® wrote:
| Quote: | This is not rocket science but I would like to know how to find out which
end is bad.
|
The way to find out which end is bad, is to repair one end (doesn't matter
which). After you've made the repair, you'll always find the problem was
at the other end. ;-) |
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David Magda
Guest
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| Posted:
Tue Jul 12, 2005 8:20 am Post subject:
Re: Which end is bad of cable |
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James Knott <james.knott@rogers.com> writes:
| Quote: | The way to find out which end is bad, is to repair one end (doesn't
matter which). After you've made the repair, you'll always find the
problem was at the other end. ;-)
|
Unless you botched the repair.
Or you picked the wrong end (you cut the good one) and botched the new
crimp so that you now have two bad ends.
It happens.
--
David Magda <dmagda at ee.ryerson.ca>
Because the innovator has for enemies all those who have done well under
the old conditions, and lukewarm defenders in those who may do well
under the new. -- Niccolo Machiavelli, _The Prince_, Chapter VI |
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James Knott
Guest
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| Posted:
Tue Jul 12, 2005 3:17 pm Post subject:
Re: Which end is bad of cable |
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David Magda wrote:
I guess you missed the ";-)". |
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Tekkie®
Guest
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| Posted:
Thu Jul 14, 2005 6:40 am Post subject:
Re: Which end is bad of cable |
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James Knott posted for all of us...
I don't top post - see either inline or at bottom.
| Quote: | Tekkie® wrote:
This is not rocket science but I would like to know how to find out which
end is bad.
The way to find out which end is bad, is to repair one end (doesn't matter
which). After you've made the repair, you'll always find the problem was
at the other end. ;-)
Well, did that... new plug on end A no good. New plug on end B no good. |
Repeat again no good. I gave up as it was going to be temporary & an unused conductor.
Did check my checker though & it was okay. I wonder at this point if there was an open
somewhere along the span...
--
Tekkie |
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Jgolan
Guest
|
| Posted:
Mon Jul 25, 2005 4:20 pm Post subject:
Re: Which end is bad of cable |
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Some connector are only meant to work with stranded or solid
cable......you may be using the wrong type for the cable.
-------------------------------------
Tekkie® wrote:
| Quote: | James Knott posted for all of us...
I don't top post - see either inline or at bottom.
Tekkie® wrote:
This is not rocket science but I would like to know how to
find out which
end is bad.
The way to find out which end is bad, is to repair one end
(doesn't matter
which). After you've made the repair, you'll always find the
problem was
at the other end. ;-)
Well, did that... new plug on end A no good. New plug on end B no
good.
Repeat again no good. I gave up as it was going to be temporary &
an unused
conductor.
Did check my checker though & it was okay. I wonder at this point
if there was
an open
somewhere along the span...
|
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