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Soldering for beginners

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I need to replace a surface mount power socket on my laptop. It needs to be soldered on. I've bought an adjustable temperature soldering iron which includes solder sucker. Any tips? Am I crazy? I've never soldered by the way...

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I did a bit of soldering when i was a kid, and thought it was easy.

Tried it again a few years back, and it seemed much harder. I think because you're no longer allowed to buy proper solder with lead in it.

So my tip would be to find some old solder with lead in it 

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34 minutes ago, SpectrumFX said:

I did a bit of soldering when i was a kid, and thought it was easy.

Tried it again a few years back, and it seemed much harder. I think because you're no longer allowed to buy proper solder with lead in it.

So my tip would be to find some old solder with lead in it 

This. A million times yes. 

I've had exactly the same experience, easy years ago and a complete ball ache now. 

Also I can suggest buying some old PC from a car boot sale, strip it down and try soldering points on the mother board to some stripped down cable until you've got the hang of it. 

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You may find that hobbyist soldering irons don't get hot enough to melt solder on commercial products. 

My electric ones would touch the solder on my telly.  But dremel's little gas powered one works a treat. Super handy.

Biggest tip I'd give you is to remember the pointy end abd various bits back toward the handle get proper hot.  And stay that way.  If you are working with a wired one, practice moving it about while it's plugged in and turned off... it can be surprisingly awkward, cable pushes it around.  That means it can be put down  carefully but end up in your lap about 3s later.  Wear shoes, and tough trousers that don't melt.  Try not to push it against anything (like a plastick housing) that melts.

 

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20 minutes ago, thombleached said:

This. A million times yes. 

I've had exactly the same experience, easy years ago and a complete ball ache now. 

Also I can suggest buying some old PC from a car boot sale, strip it down and try soldering points on the mother board to some stripped down cable until you've got the hang of it. 

 

19 minutes ago, RichB said:

You may find that hobbyist soldering irons don't get hot enough to melt solder on commercial products. 

My electric ones would touch the solder on my telly.  But dremel's little gas powered one works a treat. Super handy.

Biggest tip I'd give you is to remember the pointy end abd various bits back toward the handle get proper hot.  And stay that way.  If you are working with a wired one, practice moving it about while it's plugged in and turned off... it can be surprisingly awkward, cable pushes it around.  That means it can be put down  carefully but end up in your lap about 3s later.  Wear shoes, and tough trousers that don't melt.  Try not to push it against anything (like a plastick housing) that melts.

 

Good advice above, wish I'd had that the first time

I am firm believer that you can fix anything that you can pay to have fixed. Si I've done it often for many items of electrical equipment including PCs, most often to fix dry joints or replace popped capacitors due to the faulty capacitor debacle.

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25 minutes ago, sexton said:

A piece of wet sponge is essential for cleaning the tip.

This has to be the right type of sponge -- cellulose, not plastic.   (or you can use natural, from the sea, sponge -- but these are unnecessarily pricey).  Damp is right, so wet it through, then try to squeeze as much water out as you can with your hand -- what is left will be about the right level of wet.

You have to set the temperature for the solder you're using -- quite a bit hotter for lead-free than old-fashioned solder.  As a guide, set the temperature to the point where the solder just melts, then turn it up about 50-100 degrees C.  You shouldn't have it too hot as it just makes everything oxidise faster and burns the flux.  A good starting point would be something like 300 C for lead, 350 C for lead-free, but don't necessarily trust the graduated dial on a cheap soldering station as it'll probably be wrong.

Surface mount is usually a bit more tricky than through-hole -- you might find it easier to first glue the component down in the right place with a dab of superglue.  (although a large connector should really have tabs to hold it on as well, so that might not be necessary).

You might find it helpful to first clean the board and connector with some (isopropyl) alcohol. Personally, I don't bother unless it looks dreadful.

In terms of technique, you have to 'tin' the soldering iron tip first, which means putting solder on it away from the component.  This is just a thin layer, not a massive glob.  With the iron up to temperature, wipe the tip on the damp sponge (drag the tip backwards over the sponge, as if trying to deposit whatever is on the tip onto the sponge.  Do this a few times at different angles so that you've done a decent % of the circumference of the tip).  Then dab the solder onto the tip until it has gone silver all round.  You can put loads on if you like, but wipe off excess (on the sponge) to give just a thin layer before actually doing the soldering of the joint.

Then you can solder the joint.  Apply the tip to the joint between the board and the component.  After about 1-2 seconds apply the solder to the joint -- ie, get it to the point where it is touching board, component and iron simultaneously.  You don't want to be applying it to the tip directly, even though it is tempting as it melts so much better directly onto the tip -- but this doesn't help it get into the joint where it belongs.  Applying it directly to the joint (ie, just board-component, a fraction away from the iron) is better.

Don't worry too much about appearance, but you should be able to see the solder flow and fill the joint between the board and component.  If you end up with a massive globule of solder absolutely dwarfing the joint then this is probably a bad sign, and masks that the solder hasn't flowed properly -- clean it up (with the sucker), perhaps turn up the iron 25 C and do it again.

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I find this depressing. I thought it was about soldiering, and how f8cking hard you are:o. Now I understand you want to put a socket on a circuit board.

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One thing I sometimes do to get around the "seem to need three hands for this" problem is to cut off a tiny little bit of solder and place it where I want it to melt before applying the heat. I'm usually doing non-electrical stuff, with flux applied separately, when I do that but I don't see why it wouldn't work for electrical applications. Crocodile clips on the end of an adjustable arm are quite handy for keeping things in place too.

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49 minutes ago, MrPin said:

I find this depressing. I thought it was about soldiering, and how f8cking hard you are:o. Now I understand you want to put a socket on a circuit board.

I killed a man with a red hot soldering iron.

No bastad takes my inductors and lives.

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2 hours ago, sexton said:

A piece of wet sponge is essential for cleaning the tip.

Fnarr!;)

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1 hour ago, Riedquat said:

One thing I sometimes do to get around the "seem to need three hands for this" problem is to cut off a tiny little bit of solder and place it where I want it to melt before applying the heat. I'm usually doing non-electrical stuff, with flux applied separately, when I do that but I don't see why it wouldn't work for electrical applications. Crocodile clips on the end of an adjustable arm are quite handy for keeping things in place too.

You need paste. It's the stuff they stencil onto PCBs when they do the reflow oven soldering. Nasty fumes though.

To the OP, I have about 10ks worth of rework kit and there is still a lot of stuff I can't/won't work on.

That said power connectors are fairly gross connectors and you will probably be able to do something without much hassle. The first issue is access. Can you access all the pins to apply heat. Although you imply the connector is SMT, they usually aren't. The reason is any connector like that is usually under a fair amount of mechanical stress (which is why they break) as people pull the cables in and out. So normally they are made with through hole connections. There will probably be two for the power, plus some side lugs. The biggest problem will be applying heat to all the connections at once. The connectors are often snap in, so they match up very well with the hole sizes on the board - that can make them difficult to pull out even if you can succeed in applying heat to all the necessary pins at once. You normally have to apply some pressure to pull the connector off but at the same time you don't want to either knacker the board, or more likely damage the delicate copper tracks on the board surface. Fortunately for a power connector these normally solder straight into power planes which are solid copper on the board, so you are less likely to damage them. Unfortunately these planes act as a massive heat sink, so you might struggle to apply enough heat to get the thing off in the first place. Once you've got it off you should clean up the mess. IPA as has been said will do. If the holes are full of solder then you might need to clear them with braid. Lead free is a pain to do stuff like this with.

The things you have to ask yourself on this sort of stuff is it actually the connector that has broken ? Maybe mechanical stress has just made the connections go to the board, so if you heat the pins up on the backside it may reconnect them or are you trying to repair it/ give it to a customer or just use it yourself ? If you are using it yourself for example and don't mind the loss of portability you could just solder the PSU wires direct to the board. The point being is it may not be necessary to produce a perfect repair to make it usable.

Finally I would say make sure you disconnect the internal battery before doing anything. And sponges are dead. The pros use wire wool stuff. It doesn't dry out.

 

 

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Very impressive stuff.

To be fair, what he probably doesn't show you is the 10 times he did it trying to learn how to do the process and screwed it up. That's part of the problem here. Forums are always full of bias on how someone repaired a ££££ telly with 2 minutes work. No one ever posts on how they screwed up and failed miserably.

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1 hour ago, Gigantic Purple Slug said:

Very impressive stuff.

To be fair, what he probably doesn't show you is the 10 times he did it trying to learn how to do the process and screwed it up. That's part of the problem here. Forums are always full of bias on how someone repaired a ££££ telly with 2 minutes work. No one ever posts on how they screwed up and failed miserably.

You just reminded me of desperately trying to repair traces with wire wrapping wire.

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Err on the side of using a high temperature especially when desoldering because youl melt the solder more quickly with less time for heat to propagate and damage something. When applying solder you need to heat up the surfaces being soldered so they are hot enough for the solder to melt and flow over them - don't attempt to drip molten solder onto the joint, with the right solder temp you should be able to heat the joint for about half a second or so then dab on the solder and it should flow onto the join. Dont keep the iron on the joint for more than a second or so, if things go wrong remove the iron and wait for the parts cool and try a again.

Desoldering is often much more tricky then soldering so if you manage to get the old part out without frying everything you should be sorted.

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Use lead based solder as mentioned before (fluxed cored). Also highly useful for surface mount is separate is solder wick - you can then afford to be liberal with the solder and if you have too much on a little heat form the iron just behind the end of the wick will draw up excess solder into the copper braid. A solder sucker can cause more damage  that it is worth sometime, so gentle as to can so you don't lift the traces, hence suggest using the wick.

If you have to get the existing socket off this is also likely to be a trace removing exercise - so you need to be gentle with it and it actually helps applying more solder to the joints (bridging them no problem as it will keep all the joints hot. A little trick is you can loop a thin wire behind the surface mount pads and as you heat the pads pull the wire back through under the joints, this will lift the pad away from the board and solder. The connector may have through hole ground lugs that fix the connector to the board, this is where you will need the solder sucker. If it does not work first or second time then re-solder and try again. A flux pen or flux paste is also useful. Once you have the old connector off clean off all the excess solder, use flux and the wick to clean it all up.

When refitting the connector you could use solder paste or flux core solder both will work. Solder paste can be applied with a tooth pick putting a small dob on each pad. Depending on the pith of the pads you may well get bridging again between adds but don't worry just get the wick out and draw off the excess solder.

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Watch a few videos from this guy, who repairs computers and phones commercially. He's quite happy to give out plenty of hints and tips. This may not be the best video for soldering techniques, but it is mildly entertaining.

He likes to rant and swear a lot, so just bear in mind when watching.

 

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Both soldiering and soldering cause swearing.

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4 hours ago, Gigantic Purple Slug said:

You need paste. It's the stuff they stencil onto PCBs when they do the reflow oven soldering. Nasty fumes though.

No you don't - solder-paste in only required for reflow soldering on a surface-mount production line.

Repairs and rework can be carried out with a standard soldering iron and regular solder.

If you can only get lead-free solder, then a bottle of liquid flux might also be an advantage.

You should also remove the original solder with a solder-sucker or solder-braid if you want to do the job properly.

 

XYY

                                                                                                               

The dog's kennel is not the place to keep a sausage - Danish proverb

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Advice from an old solderer?:huh:

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5 minutes ago, MrPin said:

Advice from an old solderer?:huh:

I currently work in a factory that produces surface-mount electronics, and have worked in a few repair workshops in the past.

I'll be the first to admit that I often talk a load of shite Pinny - but for once I do actually know what I'm talking about..!

Normal XYY service will be resumed as soon as possible...

;)

 

XYY

                                                                                                               

The dog's kennel is not the place to keep a sausage - Danish proverb

 

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17 minutes ago, The XYY Man said:

No you don't - solder-paste in only required for reflow soldering on a surface-mount production line.

Repairs and rework can be carried out with a standard soldering iron and regular solder.

If you can only get lead-free solder, then a bottle of liquid flux might also be an advantage.

You should also remove the original solder with a solder-sucker or solder-braid if you want to do the job properly.

 

XYY

                                                                                                               

The dog's kennel is not the place to keep a sausage - Danish proverb

I know lots of people who use paste for rework.

You use it in the same way you would for reflow - delicately coat the pad with solder, then place the IC on. You can then solder the IC down just by touching the pins. On a very fine pitch IC it's extremely difficult to solder down the pins with normal solder, because every time you try to get in you will end up bridging the pins together. I'm not talking DIP packages here, they are easy.

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