break in cat5

[christopher]

I have 2 cat 5 cables that run from the kitchen to my patch panel.

The cables came loose from a window frame and got steached when somebody opened a window.

I cut off the first 12 feet of the cables, including the bad bit and fiited new between the socket in the kitchen and a pair of krone style joiners which connect to the original wires

I have a cat5 tester and almost had it ready to role but I' have three wires that are not connected.

I have re-made the joints at the joiners and and the sockets a couple of times but still cant find the break. Ive also punched down all the Krone fittings

Is there a tecnique to trace the break to the original or new wiring.

I dont fancy putting RJ45's on the old wires as its a bit brittle and under the eaves

All i,ve got is a multimeter.

Help and direction appreciated

Parts

[tony sayer]

In article , [e-mail] scribeth thus

I suspect its pulled apart somewhere else along the line and if it were that case you'd need a TDR to find it which is something most people don't have..

However if you have Two decent pairs working then use those for carrying the signal only the Orange and Green pairs are used for normal 10/100 ethernet use.

You can find out which pairs are OK by doing a simple Ohms test with a meter .Just short say the Green and Green/White at one end with a bit of wire then check for continuity on the other end you can also do a check from each conductor to each other to see if you have any shorts which sometimes happen when cables have been pulled..

So if say you have a decent Blue pair and the Greens U/S then substitute the Blue for the Green. Done it before and its worked fine:)...

Don't use a Green and a Blue wire for instance to make a pair, it might measure OK but you won't get much of a signal down it!.

Course if its Gigabit or Power over ethernet anywhere then that won't work and you prolly end up replacing the complete length..

[Tabby]

Divide & conquer. Separate the lengths of cable anywhere you can to narrow it down. Thats about all you can do with a nothing but multimeter.

To locate the break, one of the easiest devices is a capacitance meter. Just measure cable capacitance at each end, and capacitance is proportional to the lemngth of connceted/unbroken cable. Its simple to make a C meter if you've got basic electronic skills, or you can use a sig gen, multimeter and simple filter to do the same.

NT

[brass monkey]

Really? LOL You almost covered my screen with coffee with that one Tony ;)

[tony sayer]

There is a rather simple design for one of they tho you do need a scope to work it wiv;)...

Which I suspect more people might not have..

'ang on, perhaps with a PC soundcard;?..

[Tabby]

Would a 20kHz soundcard scope be enough?

The capacitance meter approach is real simple.

NT

[tony sayer]

Have to get around to trying sometime;)..

[Andy Champ]

Ooh let's see... speed of transmission in copper is roughly half that of light. But the signal needs to go out and back, so the transit time is that of a signal going one way at a quarter that of light.

so 20kHz will give you a resolution pushing 4km.

Feel free to point out the error in my calculations!

Andy

[Tabby]

:) Well, the L & C of the cable should slow it down, but even so I can't see a 20kHz scope being usable.

NT