got a washing machine playing up, and been looking online for solutions. seems to be a well-known fault with circuit board, replace capacitor C17 etc etc. i always try and fix things myself if poss, both for money saving and learning something new, so im looking at trying a 50p fix rather than a new washer.

bought the replacement capacitor, removed the circuit board (hopefully my diagrams are good enough to get it back the same way, and now looking at the board.

i see the offending item, but when i turn the board over theres just loads of silver solder splodges.

firstly, is there an easy way of working out the right ones to heat up?

secondly, is there a recommended tutorial for tips on how to solder? never done it before, wouldnt want to melt a big silver splodge all over the board and join up things that shouldnt be joined up 🙂

thirdly, the capacitor has real long legs. do i push it through melted solder then snip off to length?

i also noticed there are a few blackish areas on the board. anything to worry about? will they have been caused by my faulty capacitor and will be fine with its replacement?

thanks for any help in learning my new skill 🙂

Just dont ask any Americans!

Sawder ffs! Just no! 😆

firstly, is there an easy way of working out the right ones to heat up?

If it’s not obvious, get a ruler an measure from the edge.

thirdly, the capacitor has real long legs. do i push it through melted solder then snip off to length?

No, remove the old component and solder. Trying to use the old solder sounds like it would be quite hard.

Also – get a solder sucker, you will need it to remove the old solder when you remove the damaged capacitor.

Get a solder sucker,do a few dummy runs on an old bit of board before you launch in to the job.Make sure everything is clean and use a good flux.

Edit: misread thread title. Solder. As you were.

You get stuff called Solder Wick – it’s basically a fine mesh tape. Press that onto the old solder with a hot soldering iron and it’ll wick it all away. Easier than a Solder Sucker IME.

http://www.maplin.co.uk/p/de-soldering-braid-1mm-width-n47fx

When you remove the capacitor make sure you note the polarity – if it is a blue can type capacitor then one side of the can will have a stripe down it. Make sure you put in the new capacitor the same way round or it will go pop.

Oh and loads of decent vids on YouTube for technique – but it’s really not rocket science. Only important thing to know is that you make the metal hot then apply solder to it, you don’t melt the solder on the iron then apply it to cold metal.

As others have said, get a solder sucker.

Also use new solder to refit cap

Use tweezers to pull out, but don’t use force, the cap after you have removed the solder as it will be very hot.

Is it an electrolytic cap, if so you need to make sure it goes in the right way. It will have a “-” on one end to show you.

Use solder wick… put the wick on the pad then apply the iron tip, do not leave the iron on any longer than is needed to pull the liquid solder away otherwise you’ll delaminate the pad from the board. The hole needs to be clear of solder then insert the new component. apply the iron to the leg and pad at the base and feed in the solder (most solders are fluxed these days), again as soon as the solder takes to both remove the iron. snip the excess legs and away you go. REMEBER too much heat is bad!!!!!.

thanks. been looking at usual places and can see the soldering irons, but no sucker or braid.

could anyone link me to an iron, flux and either braid or sucker from either toolstation, screfix or maplins at all please?

itd be good if i could get everything from one place.

thanks a lot

maplins N49FX for braid, N11BY for a cheapo iron, you can also get a bit of solder there too.

excellent, thanks.

and yeah, whats that american sawder thing all about 😀

Last time I got solder from Maplin they only stocked lead-free, which is all very nice for the environment and that, but leaded solder is MUCH easier to use especially for a hobbyist.

Have you looked to see how much a new circuit board would cost?

It might be cheaper than buying all the equipment

Trying to use the old solder sounds like it would be quite hard.

could anyone link me to an iron, flux and either braid or sucker from either toolstation, screfix or maplins at all please?

Electrical solder (as opposed to plumbing solder) has a flux core so you shouldn’t need to buy separate. This is also why you can’t just reuse old solder, the flux will be burnt off as part of the soldering process so you need to remove it and use fresh.

Or just ask a capable and willing STWer to do it?

Where are you located?

new circuit board is around £80 i think the missus said. got now to lose trying the 50p capacitor and also learn new skill/ acquire new tools for future 🙂

i assume i just tell em what im doing in the shop and theyd supply the right solder yep?

ta

EDIT:

Where are you located?

im in lincoln, but it seems too small a job to ask a fellow stwer to travel and do it for me, may as well have a bash meself. thanks tho 🙂

Don’t get into a conversation with an American about circuit boards they use an entirely different naming convention (well not quite but still can cause a lot of confusion) 🙂

Use tweezers to pull out

It’s often easier to snip the old component and then desolder the legs individually. Trying to do both at once means that the one you’ve just desoldered could ‘stick’ whilst you’re doing the other.

When using the iron, use it for a couple of seconds at a time and then wait 30s before trying again. Too much heat and you can lift the tracks off the board, then you’re in a world of pain.

What I’d do if I were you is get a strip of Veroboard and a bargain bag of resistors and practice before going anywhere near a repair.

It’s pretty easy, but you will need to get some practice on experiencing how the stuff behaves.

Electronic solder is just solder, flux core meaning there’s flux down the inside of the wire, you don’t have to add it like you do with the stuff plumbers use.

Buy some veroboard, a kit, and make something pointless as practice.

If I were removing a capacitor, I’d pull the leg with fingers or tweezers whilst heating that leg. Doens’t work with things like chips or PCB mounted sockets that can’t be flexed, but should work with a cap.

Have you got an equivalent capacitor? Needs to have the same capacitance and at least the same voltage rating.

Also check the other caps while you are there – any that are swollen are also on their way out.

It’s often easier to snip the old component and then desolder the legs individually. Trying to do both at once means that the one you’ve just desoldered could ‘stick’ whilst you’re doing the other.

I agree but you won’t be able to see the legs on most capacitors.

Here’s a tutorial from my 6yo…

[video]https://www.youtube.com/watch?v=RbJV3EgXJT8[/video]

My top tip for desoldering – if you’re having trouble sucking all the solder away from the legs/hole, try adding a bit more solder first.

Nice work gerti! She’s doing really well! 😀

My 6yo has put together a couple of little kits from Maker Faire etc (flashing badges and the like) but she’s a lot more hesitant than your little one.

(Probably didn’t help that the first time she tried it she put a nice big apprentice mark on my finger 😀 )

well she can certainly solder better than me thats for sure!! cant even desolder yet!

been to maplins, bought an iron, solder wire and desolder braid, plus a little practice board.

tried the braid, but i just cannot get the solder to melt onto it. if i put a bit of solder onto the iron it melts and smokes, so its hot enough. cover the old solder with braid, press the iron onto it but its not bringing up the old solder. just out of interest i pressed the iron onto the back of the dodgy capacitor but it doesnt seem to be melting any old solder around it, even without the braid.

capacitor is still solid in board.

Don’t use the iron dry when desoldering, you need a dot of solder to conduct the heat to the old joint.

Can’t help with the braid, I’ve never used it.

OK best thing to do is put some fresh solder onto the pad/leg then use the braid to remove the lot, also wetting the braid with fresh solder can help.

Yeah you want a little bit of solder on your iron to help make good contact and transfer the heat well. Called “wetting the tip”*

It’s also possible there is a finish on the board, like a varnish, to help protect it. So try giving the old solder a little little scrape with a stanley first.

.

* (just the tip mind. And only for a minute.)

Braid is shit – use a solder sucker. Also – make sure you have a wiping sponge – this is NOT a regular sponge, it must be designed as such or it will melt.

I am assuming your capacitor is:

*Of the same type [electrolytic/ceramic/tantalum etc]
*Of equal or higher voltage rating
*Of the same capacity/value
*Going to be put in the same way around if necessary [nearly all electrolytic caps are polarised]

If I were you I’d definitely practice – just get yourself an old circuit board with similar things on it and practice removing them without buggering it up.

Tip:
Don’t fight it when removing – if you wrestle too much [joints cooled/ leg jammed on hole etc] you can strip the traces off the board.

Bonus tip:
When you’re all finished apply a good amount of new solder to the tip, dabble it in the liquid clean solder and then flick/wipe it off. You can do this on cardboard, and means the tip will finish with a protective coating of solder and flux and not rot.

Braid is nicer to use than other desoldering methods imo. I think proper solderists possibly don’t use it because it’s wasteful, and a bit of a crutch, but for your purposes that’s not important really. For the amount of soldering I use it’s ideal

It’s also possible there is a finish on the board, like a varnish, to help protect it. So try giving the old solder a little little scrape with a stanley first.

there does seem to be a sheen on the board yes.

I am assuming your capacitor is:

*Of the same type [electrolytic/ceramic/tantalum etc]
*Of equal or higher voltage rating
*Of the same capacity/value
*Going to be put in the same way around if necessary [nearly all electrolytic caps are polarised]
yep, ive had it okayed on good authority.

whats happening at the moment is i hold the solder to the iron to ‘wet the tip’ but it doesnt melt, then it does all at once and leaves a round blob on the end of the wire, my iron doesnt actually seem to hold any.

it may be easier if i scrape the surface of the board first then. and im also practising but not having much success with braid or solder with that either. maybe im just sh1t 🙂

my iron doesnt actually seem to hold any.

It’s dirty. Gets fouled up with burnt flux and who knows what. When this happens, sand the tip back to shiny copper. Then when the solder touches it it’ll flow over the surface and make it silver. This is called ‘tinning’ btw, and it generally really helps soldering things if you tin both bits first (ie get solder to flow onto the surfaces) and then you’ll only need to add a tiny bit of solder.

However in terms of electronics, most stuff is designed to be soldered so this isn’t so necessary when you’re sticking legs through holes. But you WILL need to scrape the green/brown stuff off to get shiny metal, if there’s no solder on it already.

Solder sticks to surfaces by making an alloy with the metal where it contacts it. Which is why you can only use normal solder on some metals, and you need different solder for others. For this to happen, you need clean fresh metal surfaces.

Brings back memories of the 70’s building a “computer” with my Dad 🙂

All good advice above .. once you are on a roll you will be tempted to replace solder joints all over the place

Also – make sure you have a wiping sponge

One of these:

whats happening at the moment is i hold the solder to the iron to ‘wet the tip’ but it doesnt melt, then it does all at once and leaves a round blob on the end of the wire

Lead-free solder by any chance?

It’s dirty.

Lead-free solder by any chance?

its new, just bought it! and yes, maplins only sold lead-free.

also scraped the surface with a stanley, its scraped a bit of something off, but i still cant melt that solder and i dont want to leave the tip on for too long.

Worth mentioning, some irons are nickel coated, and you’re not supposed to sand it back. Everyone does anyway, because you only realise it was nickel coated after you’ve already sanded it back. But still.

One of these:

Agree with the diagnosis he has a dirty tip
I prefer dipping in one of these to clean:

Edit: Also prefer suckers to braid for removal as I find braid doesn’t work too well with small tips.

its new, just bought it! and yes, maplins only sold lead-free.

The last time I bought a new tip (decades ago) it took me ages to get the first tinning to stick.

Not that it really matters but I own a PCB assembly company and shown this to our senior assembly engineer…. He’s not normally a sweary bloke!! 😆 😯

What were his complaints marcus?
Always keen to learn.