Soldering / repairing string wire

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#1
Not sure where to post this so I put it in here.

I've repaired a multitude of devices over the years, from hair straighteners to ECUs.

The one thing I have never really got my head around is soldering or repairing damaged cables on devices such as headphones etc when the cable is not your usual copper wire, more a multi core braided string.

Has anybody had any experience in this?

Cheers!
 

spud1966

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#3
quite simple , use a craft knife , razor blade , and say its the blue wire , just scrap the outer side of the blue very gently , and you will see the copper inside , then flux up and repair ect
 

chookey

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#4
I know too well the cable you mean @SToNER, near impossible to get any solder on it as it is so fine and has intermingled fibres. Most times it is on equipment that has too low a value to justify my repair, on high end headphones etc; I would look to replace the full cable anyway.

Using a solder pot may work with it but there is so little surface area to work with in the first instance. If it were only 1 or 2 broken cables on low end equipment you could try twisting and then try to get some solder on it. Maybe low melting solder paste would adhere using hot air station. Best avoided where possible really, 5 or 6 strands of microscopic copper isn't intended to be soldered, the terminations have a very small crimp which will take solder.
 
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#5
If it is the type of wire I'm thinking about, I usually use a lighter (lightly put through the flame) to burn the outer surface to expose the copper.
 

Spectre

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#6
I've just remembered the sort of wire @SToNER means now.

My in ear Sennheiser headphones at work stopped working on one side so measured the resistance on the jack, open circuit on one side. I noticed where they had been sitting that there was some sticky stuff which was also visible around the strain relief. I'm guessing this is plasticiser from the moulded jack which has possible attacked the wire. Or maybe they use a solder with aggressive flux which might have started some corrosion. I might be able to tell when I open it up but I'm not that bothered and would need to find a replacement jack which wasn't 10x the size of the headphones.

Someone mentions using aspirin to take some sort of coating off here, never heard of that before.

Code:
http://electronics.stackexchange.com/questions/53028/how-to-remove-enamel-from-wire
A bit more here:

Code:
http://www.litz-wire.com/dipstripop.php
 

Seedy_r0m

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#8
I've been soldering stuff off & on since I was nipper, and although the eyesight isn't as sharp as it once was, I'd like to think that I'm fairly competent at it.

Excuse me if I'm being a bit dim, but are you describing something like co-ax cable?
If not, could you please post a pic', cheers.
 

Spectre

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#9
I've been soldering stuff off & on since I was nipper, and although the eyesight isn't as sharp as it once was, I'd like to think that I'm fairly competent at it.

Excuse me if I'm being a bit dim, but are you describing something like co-ax cable?
If not, could you please post a pic', cheers.
He means stranded enamelled wire, very fine strands. Some of these types of coating don't disperse easily with heat so it can be difficult to tin a bunch of them. Even some single strand enamelled wire is difficult to tin.
 

chookey

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#10
He means stranded enamelled wire, very fine strands. Some of these types of coating don't disperse easily with heat so it can be difficult to tin a bunch of them. Even some single strand enamelled wire is difficult to tin.
Well done @Spectre, couldn't think of the name of it.
 
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Spectre

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#11
Well done @Spectre, couldn't think of the name of it.
I used some 0.1102mm or something (no idea where that diameter comes from but it was on the spool) from work to repair silver tracks on a Amiga keyboard membrane using silver paint as a glue. I scraped the ends for that though and even then it is difficult to get all the coating off.

Went to swap some tracks over on a prototype PCB using the same wire and found I couldn't tin it with our health & safety approved solder, very low activity flux.

The strands of the wire SToNER is wanting to tin will be a fraction of 0.11mm so tinning or scraping individual strands is probably out of the question. Even if you could use an iron to tin the individual strands it usually creates a ring of crispy coating between the coated and tinned bits which needs to be crushed or scraped off, somewhat awkward when the wire is multiple strands.

I've recently tidied up my work area at home so I might try a few methods as I will be doing this with my headphones, also I have some good microscopy equipment to inspect. Probably won't be able to practice on the wires from work though even though there are much finer ones than 0.1mm because they are old, like from the 1960s, and the coatings will probably be very different (and more toxic :)).

I'm thinking chemical stripping with acetone but as it is stranded it will wick the liquid.
 
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#12
Sorry about the delayed replies, I have been away on a holiday to Italy for a long weekend.

It's not often I give up, but in this case I think I will.

I noticed that the headphone flex is very good quality and the wires are all moulded separately into the flex next to each other. None of the wires / strings will ever touch each other as the cable is flat rather than all bunched together.

IMG_3049.JPG
 

trevortron

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#13
I feel your agony @SToNER, it is frustrating when something cannot be repaired thanks to a silly stumbling block such as this.
I have usually been lucky with these wires- using a flat soldering iron tip, well laden with solder to heat and melt the insulation, then using a blunt (pen knife) blade to gently scrape away the gunge. And if you don't mind a little bit of pain, quickly twisting the strands together while still hot definitely helps.
I do like @Spectre 's 'chemical' idea- I might give that a try some time.
It does sometimes make you wonder how the makers managed it in the first place!
 
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Spectre

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#14
I didn't get round to repairing my own headphones but have replaced a jack on some recently. I see that wire had Kevlar in it. Then I found it wasn't the jack but the headphone end...

The insulation receded with a 420C soldering iron and a solder with a reasonable flux in it. Not a particularly aggressive flux but it tinned without problem. Probably not a good idea to breathe much of that :).
 
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KhuramG

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#15
Gents,

My bike has developed a ECU problem.

Bike CBR600F 2011 - ECM (38770-MGM-D11).

After spending days of comprehensive testing I have concluded, on the black 32 pin connector at the back of the ECM unit (pin 3) which is the coil driver for the left hand side that controls spark coils/plugs 2&3 is short/not working which would need replacing.

I have not tried opening the unit as I understand it is full of silicon compound and I do not want to damage it further.

Can anyone help repair this for me - need to source the driver chip and soda a new one back on the PCB.

Any help/advice will be very much appreciated. I don't want to pay £300 to stealers who also want me to change the lock and pay for additional keys.
 

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chookey

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#16
I'm guessing that trying to repair your unit would be nigh on impossible. I have worked on encapsulated repairs before when the components were fairly standard through hole types and it was a lengthy process not guaranteed to be successful. With surface mount technology the chances of not breaking surrounding components are almost nil and then identifying them with the lack of circuits is again extremely difficult.
 

bilabonic

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#17
Firstly you need magnification of some sort, i've used Kynar wire and even Magnet wire or enameled wire off old transformers....Who remembers the first Wii Chips, then we after that we had to dremel the chip to access the pins/connections !! less than a mm !!
 

Spectre

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#18
I'm guessing that trying to repair your unit would be nigh on impossible. I have worked on encapsulated repairs before when the components were fairly standard through hole types and it was a lengthy process not guaranteed to be successful. With surface mount technology the chances of not breaking surrounding components are almost nil and then identifying them with the lack of circuits is again extremely difficult.
Some of that slightly spongy potting compound comes off quite well but there's only one way to tell :). Looks like you'd have to destroy the case on that ECU though.
 

silverdale

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#19
I use to do the first enigma chip for Xbox , Wii, PS2 and the odd atmel :), .I have a picture of that leg job and Dremel for the Wii I did, I will dig it out
 

KhuramG

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#20
Some of that slightly spongy potting compound comes off quite well but there's only one way to tell :). Looks like you'd have to destroy the case on that ECU though.
Yep, job for the weekend - I guess i've got nothing to loose - this unit in its current state is no good so good to experiment with and learn :p
 
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