Soldering question

I am trying to replace the power socket on a laptop, however my cheapo soldering iron won't melt the solder on the pcb. Would a more expensive soldering iron melt it? Or could they have used some strange solder which doesn't melt again? Any advice appreciated, or recommendations for irons! Thanks

I suspect lead-free solder has a higher melting point…

I've done this. Borrowed a decent high temp soldering iron from a mate and it worked well.

Worth giving the solder points a scrape first to make sure you are in contact with the solder as I found they had put some kind of plasticy coating over it.

Have you tinned the end of the soldering iron?

What Simon said. Cheap irons have trouble melting full-fat lead solder at the best of times, and often fail dismally on the higher melting point of lead free stuff.
You need a hotter iron.

some boards have a clear lacquer over them after theyve been dipped.

Decent soldering iron (25W or 50W), tin the tip first with a bit of solder and flux and you'll have no problem. Also not a massive soldering tip as you will risk spreading the heat and solder over other joints

Thanks chaps- not sure if I have tinned the tip, is that just covering the tip with solder? doesn't it melt?

I'll try the lacquer thing. If I need a new iron does anyone have any recommendations/things to avoid? Problem with internet is there are loads of cheap ones which look good on paper but (probably) don't work,e.g. this

Lead free solder does melt at a higher temp but not massively so you iron is almost certainly not up to it especially if the tab is large or connected to a power or ground plane. this just heat sinks it and your iron cant keep up!. When lead free came in it caused and is still causing massive problems even for the big electronic boys so you are not alone. be careful though cos using a more powerful iron can cause problems with localised heating of the pcb. Use desolder wick as it will remove the solder as soon as it melts and reduces the possibility of damage. As for the iron you linked…..err maybe not for a lot of use but for the price maybe worth a try.

Get some flux matey it will help 😉 any cheapo soldering iron will de-solder any PCB component in a laptop.

If it is one of those square power sockets then I found that there are metal lugs bent over holding them in too, under the solder. — Just rip it out!

not sure if I have tinned the tip, is that just covering the tip with solder? doesn't it melt?

it's supposed to! Tinning means wetting the tip of the iron with a layer of molten solder which allows more efficient transfer of heat to the workpiece

Soldering irons tend to run at the same temp but have different tip sizes ,which can put down varing amounts of heat (in to the the piece being worked)it is important to match the tip size to the job in hand.
Too small a tip -not enough heat input to melt the solder
Too bigger tip – too much heat can cause lots of problems track lifting etc

\get some solder with flux ( most has)and tin the tip

How
let the tip come up to heat then melt fresh solder on the tip let the flux burn off then dab the tip on a wet sponge or cloth to clean the tip ( if the tip isnt a nice clean shiny silver colour you will need to gently clean the tip with a wire brush or file ( oil free)then start from the top.

Once the tip is tinned dab a small amount of solder on to the tip to enable good heat transfer then place against the piece being worked.

A good tool will be a pair of thin and i mean thin pliers ( thick ones will draw out too much heat from the piece being worked) and a SOLDER SUCKER or at a push copper braid (to draw off the excess solder)

Dont leave the heat on for too long as you will damage the track and poss the board.

the varnish as mentioned above is called conformal coating and it can some times be burnt off with the iron and sometimes scraped off,

If you want any more help just shout

getting a good soldered joint is more complicated than just melting a blob of solder as you have found its not rocket science but the basics have to be followed otherwise the joint will fail.

I spent 3 years wielding a soldering iron in another life repairing fighter aircraft circuit boards from the 50-60s and no I'm not that old aircraft arnt cutting edge contrary to popular opinion other than the sneaky stuff.

Many many years ago, spent two years working as an MOD standard wireman, working in a factory making all sorts of military electronic assemblies. My soldering course took a whole week! Contrary to popular belief, soldering correctly is not an easy skill (and i'm far more dexterous than most).

You need an iron withh a fine tip. Big clunky tips are useless for fine work and you'll likely do damage.

Get the tip of the iron tinned, by getting a bit of damp sponge, or tissue and wiping the hot tip on this. Then when the iron is at full heat, melt some solder until it runs over the tip.

Repeat the wiping routine until the tip is silvery with solder.

Get some solder braid and tin about 2 inches from end with a small amount of solder to encourage the wicking effect when you use the braid on the joint and to mitigate later excess heating of the pcb.

Place the braid between the joint and the iron tip and apply very gentle pressure, whilst dabbing on a tiny bit more solder. When the joint softens and you see the solder flow into the braid, slowly draw the braid as it soaks up the solder, but keeping the iron resting on it. Don't stay on too long as you may do damage to the board and it's components. Wait a while to let things cool down between each go.

I'd only use a solder sucker of there is a large amount of solder on the joint, but modern laptop pcb's are made in flow wave machines and there's minimal human handiwork, so you'll rarely get big wads of solder (other than on big heavy joints).

You can get different temp irons! Silver solder has a higher melting point and we used to use Oryx or Weller heat controllable irons that went up to 350c. I can't remember what they were set to i'm afraid, but always use the lowest temp required to melt the solder. Silver solder has a higher melting point, but you won't be needing this. If you want to chance it with a cheap iron that's too hot, try unplugging just as you are about to use it. This'll help as it cools, but you'll need to time things right.

Use a pair of tweezers and heat the power socket leg as you gently lift it. Be careful not to raise the track of the board and keep away from chip capacitors, they'll leach in seconds.

When the socket it out. clean up any remaining excess solder with braid and isoproprl on a cotton bud.

Mount the new socket, make sure it's seated correctly and flow in a nice fillet around the leg (no blobs).

DON'T blow on the joint to set it either.

Clean off any flux with isopropryl on a cotton bub.

Job done.

Someone might have mentioned this, but I find my soldering tips become less and less effective over time. New tips always work much better. This is with a gas soldering iron though, so may be something to do with that.

Thanks all!

For a power socket on a laptop mobo you'll need a fairly large tipped iron, or a small tipped iron with a very high temp setting. Normal cheapy 25w irons generally can't muster the heat required to reach the required temp on large connections and will just not touch it, or rather it will take forever to reach temp which will damage the components/tracks. Other than that I'd follow spongebobs advice. Lead-free solder is manky stuff that requires more care than normal stuff, but doesn't need much higher temps to melt, but tinning the tip is vital to all of this as without a decent liquid surface you just can't transfer the heat to the joint.

Best one I've found for this is a gas-fired iron, fine tip and 75W equiv heat, whips them out in seconds without excessive board heat. Done a few now, considerably easier than TSOP packages I'm currently dealing with by hand!