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Finding a break in a wire

I have a number of relatively expensive headphones that have stopped working. There are apparently breaks in the wires caused by fatigue. Since the connections at the ends are molded, it's hard to simply replace the wire. Ideally, I'd like to find the break, open the insulation at that point and patch the break. Unfortunately, I can't think of any way short of a time domain reflectometer to pinpoint the break.

I realize that in extremis I can cut the wire at both ends close to the molded edges and patch in a new wire, but I am looking for something less drastic. Has anyone discovered any good techniques for such situations?

--
Nelson
Reply to
Nelson
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Give this tip a go but if you do please report back, whether successful or not. I suspect it won't work because of the close proximity of adjascent wires.

Searching for a buried wire or even trace tracing in a multi-layer board. Where you can only connect a signal to one end. Make a sniffer from the pole pieces and coil of a high ohmic relay. I used a shallow flat pack (small diameter solenoid) 48V relay as you used to find on telecom boards, this one an NEC MR48S 24, 4200 ohms, fixed to an empty ballpoint pen barrel. Connect to an op-amp with high gain and feed into a crystal earpiece. Connect an audio sig gen set to about 1KHz, square wave and high amplitude and sniff with the pole piece/s in translating and rotation to zero in on maximum tone, position and direction of the conductor. For more discrimination connect a DVM on AC range in place of earpiece and set sig gen at about 8KHz for highest response. For single connection, ie not current through the conductor then detection distance with earpiece only about 10mm but about 50mm for 8KHz and DVM.

other tips off URL below

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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Reply to
N_Cook

In 99% of cases it will break where there is the most movement or strain - which is usually just up from the plug.

I bought quite a nice little signal tracer kit off Ebay - it sends an RF signal up the wire and uses a separate receiver to trace it. Works well where I've tried it - but not used it for mm accuracy.

--
*Time is the best teacher; unfortunately it kills all its students.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.
Reply to
Dave Plowman (News)

Over the years I've noticed that "strain reliefs" often cause the exact problem they're supposed to prevent. The strain relief is too short and too stiff.

Reply to
William Sommerwerck

Forget it.

When it's got to that state it just breaks again somewhere else inside a month.

Graham

Reply to
Eeyore

I repair quite a few personal mics as used with radio mics, and they invariably go close to the connector. Where the cable clamp is. Extending the support just means the cable fails slightly further up. ;-) Since on many it's pretty difficult if not impossible to replace the cable I now prefer to have it break as close to the connector as possible. This gives the maximum number of repairs before the cable becomes too short.

--
*Being healthy is merely the slowest possible rate at which one can die.

    Dave Plowman        dave@davenoise.co.uk           London SW
                  To e-mail, change noise into sound.
Reply to
Dave Plowman (News)

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