What to use in leiu of solder to connect wire to pcb with limited equipment?

[electroniclearner820327]

This is a critical lead I use every day: the lead which charges this very laptop I am writing this on.

It has a step down converter and one of the soldered wires broke free which I noticed was the cause of it suddenly stopping charging at all.

Would be a quick 5 minute job to resolder if I was at the garage with mains electricity but I am not.

I took my electrical box with stuff like wire and heatshrink and croc clips but no soldering iron. Didn't envision needing one of those 'on the road'.

There is still a blob of solder there. I wouldn't want to risk melting the whole thing with some ham firsted attempt with a lighter or such.

Can I use something to stick it back down?

I can probably improvise something with maybe just a crocodile clip to clip it back on after attaching it to the wire that has come free.

Any other suggestions?

Hmm I have some builder's silicone that might work well to fasten it in place until a proper solution is found.

[Xena E]

Visit a hardware shop/tool stall on an open market and buy a portable butane soldering iron...

X

[Ian.M]

Get a gas or battery soldering iron!   There is no way to re-attach it reliably without soldering that doesn't risk it shorting out, or burning up due to excessive contact resistance.  Nearly all conductive glues are a waste of time
 for something like this, and the high silver content ones that may work cost an arm and a leg and are only available mail order from specialist suppliers..

However, if I *had* to try to bodge it, the joint was near the board edge and there was enough space either side to minimise the risk of shorts, I'd take one contact + screws from a 3A screw terminal block, and cut a slot in the end of the contact just wide enough for the PCB so it could be slotted over the board edge and the screw tightened down onto the pad enough to make a good contact (Don't overtighten - as there is a hollow in the contact under the other side of the PCB, you will break the PCB).  Clamp the wire in the other end of the terminal block contact as normal and insulate everything as best as you can!

[coppercone2]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

[Xena E]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

What do wirenuts tell you 🤭

[Ian.M]

Before electric soldering irons, there were soldering irons heated by placing the end in a fire.   You can make one out of a block of copper or brass large enough to hold the heat for long enough to make a couple of joints, fitted to a thin steel tube (so it conducts heat poorly) in a wooden handle.  Either file the block to a point as the working tip, or drill a hole in it and swage in a piece of thick copper wire and file the end to a bevel to make the tip. 

[themadhippy]

on the road

you got a car battery ?if so arc weld it back

[coppercone2]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

What do wirenuts tell you 🤭

they may have some degree of cold welding not present in cage clamps and might as a result have higher durability in certain conditions

their saying that big ship that crashed into the bridge started with a wago


it is the inverse operation of wire wrapping (possibly)


wire nut:
https://media-cldnry.s-nbcnews.com/image/upload/t_fit-1000w,f_auto,q_auto:best/MSNBC/Components/Photo/_new/110504-space-gravity-730p.jpg

european clamp
https://c8.alamy.com/comp/DJ09GF/antique-paperweight-on-the-top-of-the-old-pile-of-papers-DJ09GF.jpg

[Xena E]

on the road

you got a car battery ?if so arc weld it back

🤣

[Xena E]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

What do wirenuts tell you 🤭

they may have some degree of cold welding not present in cage clamps and might as a result have higher durability in certain conditions

their saying that big ship that crashed into the bridge started with a wago


it is the inverse operation of wire wrapping (possibly)


wire nut:
https://media-cldnry.s-nbcnews.com/image/upload/t_fit-1000w,f_auto,q_auto:best/MSNBC/Components/Photo/_new/110504-space-gravity-730p.jpg

european clamp
https://c8.alamy.com/comp/DJ09GF/antique-paperweight-on-the-top-of-the-old-pile-of-papers-DJ09GF.jpg

Anything that allows cold flow of conductor material to loosen the gas tight contact of a joint is crap.

A lot of systems are popular because they are cheap/quick/easy. Not always because they are good.

X

[electroniclearner820327]

Get a gas or battery soldering iron!   There is no way to re-attach it reliably without soldering that doesn't risk it shorting out, or burning up due to excessive contact resistance.  Nearly all conductive glues are a waste of time
 for something like this, and the high silver content ones that may work cost an arm and a leg and are only available mail order from specialist suppliers..

However, if I *had* to try to bodge it, the joint was near the board edge and there was enough space either side to minimise the risk of shorts, I'd take one contact + screws from a 3A screw terminal block, and cut a slot in the end of the contact just wide enough for the PCB so it could be slotted over the board edge and the screw tightened down onto the pad enough to make a good contact (Don't overtighten - as there is a hollow in the contact under the other side of the PCB, you will break the PCB).  Clamp the wire in the other end of the terminal block contact as normal and insulate everything as best as you can!

Is the risk of shorting a fire hazard? I ask particularly because this thing is right by my bedding! I will take the fuse out when I switch off to be safe but have to get it up again asap because I have to use the internet/laptop every day to solve problems like the op.

Actually I will electrical tape it. It is nearly bedtime and looking into the tangle of wires for which one this is (ye I have not made it easy for myself with naming everything) at this time will be no simple task since they are all crammed behind the bed.

Btw what is the wooden board called where you screw all your devices to in the system? Is it it generally called circuit board as well? feels somehow wrong since I am used to that term only for pcbs.

This is actually a sorry state of affairs which must be rectified to tide me over as without my laptop my whole ecosystem will collapse. No access to internet is bad. Don't have access to mail order or local shops which will sell soldering irons right now as in a rural place.

One of my priorities on my list is getting some kind of mail solution but it isn't sorted yet.

I have had all sorts of electrical issues like lack of solar power but a tiny soldered joint was the last thing I was thinking about which would stump me!

So to get a way to solder the existing one back with limited tools will be the best way until I can get more exotic items ordered to prevent such an eventuality again. So perhaps the fire poker type of thing noted above.

Not sure what pointy metal thing I have around which will do the job though.

Open to suggestions for common items which I may have.

Will heating a fork with a lighter get it to hot enough to melt the solder blob to reattach the wire?

Getting some inspiration from this useful article: https://kunkune.co.uk/blog/soldering-without-a-soldering-iron/

Heating a screw looks like a good candidate.

[coppercone2]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

What do wirenuts tell you 🤭

they may have some degree of cold welding not present in cage clamps and might as a result have higher durability in certain conditions

their saying that big ship that crashed into the bridge started with a wago


it is the inverse operation of wire wrapping (possibly)


wire nut:
https://media-cldnry.s-nbcnews.com/image/upload/t_fit-1000w,f_auto,q_auto:best/MSNBC/Components/Photo/_new/110504-space-gravity-730p.jpg

european clamp
https://c8.alamy.com/comp/DJ09GF/antique-paperweight-on-the-top-of-the-old-pile-of-papers-DJ09GF.jpg

Anything that allows cold flow of conductor material to loosen the gas tight contact of a joint is crap.

A lot of systems are popular because they are cheap/quick/easy. Not always because they are good.

X

If its cold welded, its basically the highest class of wire bond there is.


A good ferrule might be gas tight but the clamp you put it in is anything but. And putting a cylinder bare wire into the clamp, that's basically a point contact, and it has to go through a stamping too. Even if you bend it into a square with a ferrule tool, its still dodgy interface because its connecting to a stamping, their not super flat


While with a wire nut you get a compressed helix of pure copper pressed together by square edge conical spring that not only compresses it with great force but also possibly anchors and conducts itself with a cold weld.

A robust spring might be less likely to fracture then the cage clamp stamping. Even if it does break, if you do it right, it will just turn into two springs that are still compressing wire, based on the number of turns (i.e. using the correct wire nut size) it is very reliable


And do this experiment, get that crimp that everyone tells you is cold welded solid, cut it off with a tooleand pry out the strands with a pick, and see that its basically BS.


The cold weld at the edge of sharp rectangular spring (oriented with a corner facing the object to be compressed) DOES have a chance of cold welding though.


The cage clamp is a paper weight. The wire nut is like getting something stuck inside of a sharks mouth


But the biggest problem with cage terminals is that they are plated, formed,thin sheet metal objects. things can really go wrong here.

[JustMeHere]

Some laptops have a modular board for the power supply.  This is because the power jack breaking in the manner you describe is very common. 

If the power is connected to a sub-board and not the main board, just order a replacement sub-board.

[IanB]

This is a critical lead I use every day: the lead which charges this very laptop I am writing this on.

It has a step down converter and one of the soldered wires broke free which I noticed was the cause of it suddenly stopping charging at all.

I am sensing a pattern here:

"My multimeter leads keep breaking."
"My laptop charger lead has broken."

Are you perhaps being excessively clumsy? Wires break if you bend them too sharply, or if you yank them, or pull on them. After you get this lead repaired, you might think carefully about how you manage to break things so much.

[JustMeHere]

This is a critical lead I use every day: the lead which charges this very laptop I am writing this on.

It has a step down converter and one of the soldered wires broke free which I noticed was the cause of it suddenly stopping charging at all.

I am sensing a pattern here:

"My multimeter leads keep breaking."
"My laptop charger lead has broken."

Are you perhaps being excessively clumsy? Wires break if you bend them too sharply, or if you yank them, or pull on them. After you get this lead repaired, you might think carefully about how you manage to break things so much.

Wow, really?
Power port failure is one of the most common things that happens to a laptop that gets moved around a lot. 
And servicing the connectors on a multimeter is something that just needs to be done periodically.  Just like needing to clean off the selector switch.

[IanB]

Wow, really?
Power port failure is one of the most common things that happens to a laptop that gets moved around a lot. 
And servicing the connectors on a multimeter is something that just needs to be done periodically.  Just like needing to clean off the selector switch.

Yes, really. There are two kinds of people in the world. People who break things, and people who don't. People who break things get broken cables, broken phones, broken everything. This is not random.

The people who break things are not just unlucky; they are simply more clumsy, more careless, or more reckless than other people.

Learning how to avoid breaking things is a life skill, something to be acquired. If you break something you own, you must always learn how to take responsibility for it. If it broke, it was your fault. Understand how it broke, and do things differently in future.

[Analog Kid]

Yes, really. There are two kinds of people in the world. People who break things, and people who don't. People who break things get broken cables, broken phones, broken everything. This is not random.

The people who break things are not just unlucky; they are simply more clumsy, more careless, or more reckless than other people.

I think you're being far too hard on "people who break things" and far too lenient on those who make stuff that gets broken.

Yes, I've broken things myself where it was definitely my fault.
I've also had things break (e.g., the power connector on a MacBook) that was not at all my fault, but the fault of the component under normal usage.

[Xena E]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

What do wirenuts tell you 🤭

they may have some degree of cold welding not present in cage clamps and might as a result have higher durability in certain conditions

their saying that big ship that crashed into the bridge started with a wago


it is the inverse operation of wire wrapping (possibly)


wire nut:
https://media-cldnry.s-nbcnews.com/image/upload/t_fit-1000w,f_auto,q_auto:best/MSNBC/Components/Photo/_new/110504-space-gravity-730p.jpg

european clamp
https://c8.alamy.com/comp/DJ09GF/antique-paperweight-on-the-top-of-the-old-pile-of-papers-DJ09GF.jpg

Anything that allows cold flow of conductor material to loosen the gas tight contact of a joint is crap.

A lot of systems are popular because they are cheap/quick/easy. Not always because they are good.

X

If its cold welded, its basically the highest class of wire bond there is.


A good ferrule might be gas tight but the clamp you put it in is anything but. And putting a cylinder bare wire into the clamp, that's basically a point contact, and it has to go through a stamping too. Even if you bend it into a square with a ferrule tool, its still dodgy interface because its connecting to a stamping, their not super flat


While with a wire nut you get a compressed helix of pure copper pressed together by square edge conical spring that not only compresses it with great force but also possibly anchors and conducts itself with a cold weld.

A robust spring might be less likely to fracture then the cage clamp stamping. Even if it does break, if you do it right, it will just turn into two springs that are still compressing wire, based on the number of turns (i.e. using the correct wire nut size) it is very reliable


And do this experiment, get that crimp that everyone tells you is cold welded solid, cut it off with a tooleand pry out the strands with a pick, and see that its basically BS.


The cold weld at the edge of sharp rectangular spring (oriented with a corner facing the object to be compressed) DOES have a chance of cold welding though.


The cage clamp is a paper weight. The wire nut is like getting something stuck inside of a sharks mouth


But the biggest problem with cage terminals is that they are plated, formed,thin sheet metal objects. things can really go wrong here.

Erm... OK.

Just for the record I'm not trying to promote any kind of wire connection method over wirenuts I dont like Wagos, screw connection blocks (chocky blocks) either,  I just dont think any kind of splicing device for, in particularly, fixed domestic wiring is acceptable as it's not necessary and introduces a potential failure point.

Splicing of cables is pretty much unheard of in my locality and joints of any kind in wall cavities roof spaces and behind ceilings are expressly forbidden in any new installations. I don't know under what circumstances anyone would want to use wire splicing devices in a fixed domestic installation except for "botchery".

Connections at distribution boards/consumer units are all provided with line, neutral, and protective connections as required. Lighting switches, luminaries, power sockets, appliance connections all have built in terminations to suit their use. Wire ended fixed appliances have to be connected at spur outlets.

What I'd like to know, is if wire nut twist connectors are the only safe form to connect wiring, how is that implemented in your locality, are your breakers for instance provided with wire  terminations that wirenuts can be screwed onto?

I will repeat, IMO any connection that doesn’t provide a gastight joint that also prevents cold flow of the conductor material will inevitably become high resistance and eventually fail.

Its not a perfect world though.

Regards,
X

[themadhippy]

Splicing of cables is pretty much unheard of in my locality

Think you need to get our more and lift a few floorboards,or maybe join the holes n poles team looking after your local distribution network.

[Xena E]

Splicing of cables is pretty much unheard of in my locality

Think you need to get our more and lift a few floorboards,or maybe join the holes n poles team looking after your local distribution network.

Was referring to domestic property wiring... I'm sure linesman work isn't twist n tape

Do you hack cables together with wirenuts, chockblocks or Wagos in lofts, walls, and ceilings? It's just not necessary.

The village I live in had a domestic property burn down because a sparky did a joint in a cavity (how, IDK), that was later blown full of insulation, there was a fire, fortunately the family survived.

Maybe that guy made another 20 quid from jointing a cable, who knows?

Now I wasn't suggesting sketchy stuff didn't happen, I do "get out" and have seen some proper abortions, but they've all been done in the names of quick and cheap, and in defenceof 99% of the trade, normally perpetrated by the property owners... I'm just saying that it shouldn't happen now.
Regards,
X

[Analog Kid]

Why are people going off on splices in household power cables when the OP's question obviously is about a low-voltage repair on the secondary side of a power supply?

[tooki]

hindu youtube got you bro

the theme to all the electronics videos is macguyver last man on mars

I started to think the only way to distinguish between any worlds (because food quality is too much of a contention issue, no one really knows what is actually better) is to look at the style of electrical interconnects.

What do wirenuts tell you 🤭

they may have some degree of cold welding not present in cage clamps and might as a result have higher durability in certain conditions

their saying that big ship that crashed into the bridge started with a wago

In all fairness that investigation is not finished, and we don’t know whether the involved WAGO terminal block was the cause of the failure. (It could, for example, have been a broken wire at the block, or a block damaged by improper handling, etc.) We need to wait this out and see what the materials analysis shows.

[themadhippy]

Do you hack cables together with wirenuts, chockblocks or Wagos in lofts, walls, and ceilings? It's just not necessary.

hack no,make an electrically safe joint  using suitable designed and rated materials like wagos yes.As for not being necessary?,well if your happy to pay for a  rewire every time you want to alter the electrical layout in your house, fairy snuff.

because a sparky did a joint in a cavity (how, IDK), that was later blown full of insulation,

sounds more like someone broke the golden rule of not running cables in the cavity.

and we don’t know whether the involved WAGO terminal block was the cause of the failure. (It could, for example, have been a broken wire at the block, or a block damaged by improper handling, etc.)

it could also be due the the cable overheating due to being surounded by insulation,or  the cable insulation breaking down if the insulation was blown polystyrene

[JustMeHere]

Wow, really?
Power port failure is one of the most common things that happens to a laptop that gets moved around a lot. 
And servicing the connectors on a multimeter is something that just needs to be done periodically.  Just like needing to clean off the selector switch.

Yes, really. There are two kinds of people in the world. People who break things, and people who don't. People who break things get broken cables, broken phones, broken everything. This is not random.

The people who break things are not just unlucky; they are simply more clumsy, more careless, or more reckless than other people.

Learning how to avoid breaking things is a life skill, something to be acquired. If you break something you own, you must always learn how to take responsibility for it. If it broke, it was your fault. Understand how it broke, and do things differently in future.

So no one should ever have to buy more than one car?  According to your theory, even the water pump should never have to be replaced, unless you're clumsy.  Metal fatigue is just a myth.  Even you shoes would last forever if you just walked correctly.   

[IanB]

So no one should ever have to buy more than one car?  According to your theory, even the water pump should never have to be replaced, unless you're clumsy.  Metal fatigue is just a myth.  Even you shoes would last forever if you just walked correctly.   

Wear and tear is not the same as breakage.

If you have a cable that breaks, it is because you overstressed it (bent it, or pulled it). If you have a phone that breaks, it is because you dropped it.

In 30 years of using laptops (ever since they were invented), and over 20 years of using phones, I have never had a power cord break on me. Nor have I ever had a damaged phone. Never have I had a damaged test lead on a multimeter, and never have I found the need to clean the selector switch.

So, I agree, things wear out eventually over time.

But I disagree, things don't break unless you break them. If a cable has a detached or exposed conductor, you broke it. You cut it, bent it, or pulled it. It didn't do that by itself.

[electroniclearner820327]

Some laptops have a modular board for the power supply.  This is because the power jack breaking in the manner you describe is very common. 

If the power is connected to a sub-board and not the main board, just order a replacement sub-board.

This is moot. The whole issue is I don't have access to anything at the moment!

[electroniclearner820327]

This is a critical lead I use every day: the lead which charges this very laptop I am writing this on.

It has a step down converter and one of the soldered wires broke free which I noticed was the cause of it suddenly stopping charging at all.

I am sensing a pattern here:

"My multimeter leads keep breaking."
"My laptop charger lead has broken."

Are you perhaps being excessively clumsy? Wires break if you bend them too sharply, or if you yank them, or pull on them. After you get this lead repaired, you might think carefully about how you manage to break things so much.

Correlation != causation.

That is specious speculation that it IS the cause as you are implying as a foregone conclusion.

There could be many reasons other than me being heavy handed for example, the most likely cause, that both the items in question are extremely cheap.

I am very careful with things I own thanks very much. Just because I made a couple of posts about ones I have had issues with does not say anything of the hundreds that I have had over the years and treated very well, just like I did these as best I could, and never had cause to make posts about because they work flawlessly.

[electroniclearner820327]

Why are people going off on splices in household power cables when the OP's question obviously is about a low-voltage repair on the secondary side of a power supply?

Seems things got way off course in my absence overnight! The cherry on top, 'victim blaming' me for it breaking in the first place.

Anyway I just managed to fix it.

I tried first with heating a small screwdriver and lighter which was a total fail. The lighter would not get it hot enough and I don't think it even made a dent in the solder.

Tried a couple of other metallic items to the same effect.

Next I tried with heatsink which was a success. Awkward, as I was trying to fix back a wire onto a corner terminal connection on a small pcb, but successful. I have used this same technique to make junctions on wires before. Messy but the result was a strong connection once the glue dried.

I snipped the heatshrink to make a rectangle and placed it over the corner with the wire underneath in place. I then lit it a bit, but not too much to make it overshrink and lose too much shape, then pressed down with finger. Repeat until a decent bond is made against the pcb. Gave a little wiggle and seems secure.

Dispite what the other user said about me being rough with it, I see the problem is the wires which I soldered are not held in place beyond the connection so any movement is going to put some force on the connection rather than if I say glued down the wires to the wood at the entry point to minimize the strain. It can also be because of my imperfect soldering skills, which I have done very little as usually I would be just attaching to ring connections and clamping and using heatshrink on the wire.

[ahsrabrifat]

In general, soldering is must for commercial PCBs. If it is for prototyping  like an Arduino UNO, you can include male/female/dual connectors in your design so that you can use jumper wires to connect other components to the board. Just like we do with Arduino boards.

[electroniclearner820327]

In general, soldering is must for commercial PCBs. If it is for prototyping  like an Arduino UNO, you can include male/female/dual connectors in your design so that you can use jumper wires to connect other components to the board. Just like we do with Arduino boards.

I am not saying it isn't as a general practice. People seem to miss the whole point of the thread which is that I have to make a solution with the limited tools I have with no recourse to buying more stuff.

It is like being stuck in the wilderness trying to find means to make a fire and people saying "just go to your house and cook on your electric cooker".

Anyway with it working now for the time being my attention turns to a usb/dc/battery powered solderer. I see I can get one for under £10. How come they are able to make the required heat to melt solder? I thought that making heat with electrics was one of the most costly things there are energy wise. That is why cooking on electrics is almost unheard of in the van community.

Is it just a matter of size and to heat a pinpoint to several hundred degrees is not a problem just due to the smaller surface area?

I am seeing one here that is apparently able to be powered with 3 aa batteries!

[Ian.M]

The 3 AA battery or 5V USB soldering irons are generally worthless - they just cant provide enough heat to successfully solder anything bigger than tiny pads with no ground plane or very small wires.   Smart USB C irons are a different matter, as together with a USB PD power bank capable of 20V 3A, they can provide comparable power to the tip to a mains iron or soldering station + temperature regulation.   Check the reviews on reputable tech sites before buying as not all irons are equal and many power banks cant deliver the max. USB PD output voltage and power the irons require.

You can also get 12V soldering irons with clips on the lead to go to a car battery's terminals, or a plug for a lighter socket.  They are OK, and some are capable of 60W, but they usually don't have any temperature control so you have to be pretty skilled to avoid damaging more delicate pads and traces.


Personally, I have an Orix Portasol gas iron in my toolkit, as its much easier to get a can of butane gas from just about any discount store or newsagent, than it is to recharge a USB PD powerbank off-grid without 230V AC. and its power level is adjustable.  I've had it for over 25 years, and it wasn't new when I got it.  The current equivalent model is https://portasol.com/gb/soldering-irons-kits.html?price=30-40&product_family=6

[electroniclearner820327]

The 3 AA battery or 5V USB soldering irons are generally worthless - they just cant provide enough heat to successfully solder anything bigger than tiny pads with no ground plane or very small wires.   Smart USB C irons are a different matter, as together with a USB PD power bank capable of 20V 3A, they can provide comparable power to the tip to a mains iron or soldering station + temperature regulation.   Check the reviews on reputable tech sites before buying as not all irons are equal and many power banks cant deliver the max. USB PD output voltage and power the irons require.

You can also get 12V soldering irons with clips on the lead to go to a car battery's terminals, or a plug for a lighter socket.  They are OK, and some are capable of 60W, but they usually don't have any temperature control so you have to be pretty skilled to avoid damaging more delicate pads and traces.


Personally, I have an Orix Portasol gas iron in my toolkit, as its much easier to get a can of butane gas from just about any discount store or newsagent, than it is to recharge a USB PD powerbank off-grid without 230V AC. and its power level is adjustable.  I've had it for over 25 years, and it wasn't new when I got it.  The current equivalent model is https://portasol.com/gb/soldering-irons-kits.html?price=30-40&product_family=6

What does tiny pads mean? Just small balls of solder? As these are low current dc devices that shouldn't be a problem in my case as I would only want to solder tiny couple of mm balls. It is precisely because they are so small that I use solder and just for couple of mm2 wire to pcbs for various little things like voltage step converters. For example like this: https://www.switchelectronics.co.uk/products/lm2596-dc-dc-switching-adjustable-step-down-voltage-regulator-module-4-5v-40v?_pos=6&_sid=157e55294&_ss=r

It is one like that I have fixed from the OP. Not the laptop connection to the laptop itself, but one of the wires into the voltage regulator device.

So would the 5v ones suffice for those small tasks? Bigger connections I use terminal connectors and heatshrink as mentioned above so would be redundant getting a bigger one if I was not going to use it. Will this one suffice: https://www.switchelectronics.co.uk/products/usb-powered-soldering-iron-pen?_pos=2&_sid=05d7093af&_ss=r

[Ian.M]

It depends on the width and thickness of the copper traces and wires or leads connected to the joint.  They all leach heat away from the joint, and the 10W that a 5V 2A USB iron can deliver is often not enough to get the whole joint up to the melting point of solder.  If you've got a power trace a few mm wide and a typical low voltage power lead wire leaching heat out of the joint, you aren't going to get good results with a 10W iron.  The 3x AA battery iron is particularly worthless as its max. output is around half that.

Also if you *try* to make a joint with an underpowered iron there is a high risk of board damage due to the extra time you spend on the joint 'cooking' the PCB under the pad, resulting in the pad lifting.

[IanB]

I have Hakko and Radio Shack battery irons, both of which take 4 AA cells (I use Eneloops). They work fine for joining wires and other small soldering jobs like regular PCB pads. They are nowhere near as powerful as a butane iron, and you wouldn't use them if you had other options, but as something to keep in the toolkit for emergencies, they are fine.

[mathsquid]

Hey, that's my antique soldering iron! I wasn't expecting to see it in a post today.

[electroniclearner820327]

I ended up buying one of the cheap usb ones and worked great for the small 'pads' I wanted to use it for. Melted the solder easily and job done in a matter of seconds.

Was surprised how well it worked actually.