Shortening dew strap cables.

[Danjc]

I want to shorten my cables so I don’t have lengths of cables coiled up on the scope and reduce the risk of potential interference to my data cables. 

Im guessing it is just a case of getting some RCA/Phono plugs and fitting them once I have cut my cables to the chosen length. 

[michael8554]

Fitting RCA plugs and sockets will involve soldering, so instead just solder the cut ends in the middle of the cable  together and cover with heat-shrink.

Michael 

[symmetal]

12 hours ago, Danjc said:

Im guessing it is just a case of getting some RCA/Phono plugs and fitting them once I have cut my cables to the chosen length. 

Yes it is. That's what I've done. I initially used plastic barrel phono plugs but found the threads were weak and would far to easily pull apart when unplugging them so I ended up using metal barrel plugs instead. Depending on how the PWM controller is designed (if you're using one) there may be pulsed 12V via the dew strip on the outer barrel so you need to ensure metal barrel ones don't touch each other. My arduino based one I made does so I covered my metal barrels in transparent heatshrink with a label trapped underneath saying what dew strap it was. 

If you prefer to keep the molded plastic barrel plug that came with the dew strap you can as michael8554 suggested cut a section out the middle and splice the ends together though you have to be careful to avoid shorts as it's normally screened cable which can be fiddly to join and also use heat shrink over the final joint to add some strength so that it doesn't keep bending at the join.

Many phono connectors are gold plated as they look nice and are good for low level audio signals as they don't corrode and degrade the signal. But the gold plate easily gets burnt off (as it's very thin) if they are carrying a significant current and you plug or unplug them while they're 'live'. Gold plated switch contacts are normally rated at about 50mA maximum because of this. I used nickel plated plugs, although the sockets on the PCB I made are gold plated as I had plenty in my parts bin to use. 

Alan

[Carbon Brush]

If you do not have the soldering skills or tools to connect into a phono plug then ask around locally for someone who can do it.

Splicing reliably and neatly mid-cable is (I think) more difficult.

 

[michael8554]

Even simpler, buy some "cheeseblock" - a row of tubular connectors with screwdown clamps, plastic insulated.

You cut the plastic between each connector to give single connectors. 

Stagger the cable cut slightly so that the connectors aren't adjacent, then cover with insulating tape.

That way the "bulge" isn't so fat.

Michael 

[Danjc]

Thanks for all the ideas and advice I’m going with phono plugs as I’m a bit ocd, it will all look nice and neat. 

I have had to treat myself to a new soldering station as my old soldering iron has been driving me nuts with its ridiculously non flexible short lead so I also get a new toy to play with ??

[symmetal]

As you have soldering abilities that's the best option. Having a soldering station with interchangeable size bits for different jobs makes soldering a lot easier. 

Alan

[Alien 13]

3 hours ago, Danjc said:

Thanks for all the ideas and advice I’m going with phono plugs as I’m a bit ocd, it will all look nice and neat. 

I have had to treat myself to a new soldering station as my old soldering iron has been driving me nuts with its ridiculously non flexible short lead so I also get a new toy to play with ??

A good soldering station is a joy to use especially if it has variable temp control.

I have found that even some of the cheaper plastic phono sockets are fine provided you add a bit of araldite just before final assembly but do prefer decent metal ones generally.

Alan

[Danjc]

48 minutes ago, Alien 13 said:

A good soldering station is a joy to use especially if it has variable temp control.

I have found that even some of the cheaper plastic phono sockets are fine provided you add a bit of araldite just before final assembly but do prefer decent metal ones generally.

Alan

I have put up with rubbish soldering irons for years, I think the last time I used a soldering station was way back at college. 

I’m sure when I use it it will be why the hell didn't I get one years ago ! 

[Carbon Brush]

Go for a physically small iron with about a 50watt, temperature controlled element.
By selecting different bit sizes, you can cope with most jobs from surface mount components up to big wires. But not plumbing?

When soldering, the traditional 60/40 tin /lead solder is easier to use. It melts a bit cooler than lead free.
I have though recently seen a notice from one supplier that he will only provide this to business customers, not retail.

If you grab a few bits of heat shrink sleeving in various sizes, these are useful.
You can sleeve the centre pin contact in the phono plug to avoid shorts if the cable gets twisted.
You can pack out the cable outer if it is a poor fit for the connector body.
Sleeving can provide a strain relief to prevent excessive flexing.

Don't forget. You can practice if have a spare phono plug and wire offcut.
If you are not happy with the result, just trim a couple of centimetres off the wire and try again.

Hope this helps, David.

[Danjc]

Amazon man just delivered this, only ordered at 10am this morning, 8 hours ??

[barkis]

Offset the solder jointed cores so they don't form too large a lump in the cable. Slide heat shrink as already recommended, over each core to be soldered, slide a larger 
diameter heat shrink over the main cable itself so you can shrink it with heat over the joining area. makes a neat job. 
One other reminder, place a heat shunt  between each bit of core H/Shrink, otherwise the heat will travel, and shrink the core and you won't find it easy to slide over the joints.
You can use longer shrink tubing, but you will have to sacrifice an inch or more if you don't shunt the heat away.
Ron.

 

 

[symmetal]

1 hour ago, Carbon Brush said:

When soldering, the traditional 60/40 tin /lead solder is easier to use. It melts a bit cooler than lead free.
I have though recently seen a notice from one supplier that he will only provide this to business customers, not retail.

I agree. On my Weller the temperature is set by the bit and is great for tin/lead which flows freely but lead free solder joints have that 'dry' look to them. CPC sells tin/lead solder with no issues. 

These were the plugs I used in the end as they have a plastic strain relief and aren't gold plated. Many metal ones have spring type metal strain reliefs which would most likely also need insulating if used with PWM controllers.

Alan

[Danjc]

Cheers for the tips hopefully my little cheap soldering station is up to the job ??