EBME Forums Forums Free discussion Free discussion Circuit board repairs

By way of an update (and kicking this thread back into play, for a while at least), and having cast around for a younger tech (but failing to find one gullible enough), I can now report that since my last post under this topic, I have indeed "had a go" with replacing SMD components. Only resistors, fuses and such, though (nothing overly ambitious).

Not the most beautiful repairs I have ever done, I'll freely admit. But I doubt that anyone but me will ever see (and not admire) my "handiwork"!

Two things I found useful were:- 1) Dabbing a bit of Superglue under the component in an attempt to hold it in place whilst by shaking 12 W iron approached. And 2) A x5 watchmakers' eye-glass screwed into my right socket (my best eye, in theory at least).

Meanwhile, as far as I'm concerned, it's definitely a case of:- more practise required!

OMG I can't believe you just advised people to dab a bit of Superglue under the components.

RS use to sell a smd adhesive but now I can no longer find it any more (it's not the Tak Pak), should give you a idea how popular it was. It's really only used for pick and place machines.

What you'll find more useful is if you get the component flat, hold it with the tweezers, put a bit of solder on the iron and quickly soldier one side. You can then release the component and soldier the other end and clean up the original end.

What is actually useful is: 1) A pair of fine nose tweezers and round nose tweezers. 2) Fluorescent magnifying light (unless you really do want to look like Patrick Moore? ) 3) RS flux pen

Shock! Horror!

I'm not advising folk to do anything, Chris. Just relating a tale. Let "them" do whatever they please! In fact I'm hoping they will (and are), ready to share their experiences (hopefully of success) with us all here.

Obviously, you can use any number of methods to hold stuff in place whilst you attempt to make a reasonable job of soldering it. Blue-Tack, Sellotape, ... nose bogies if you prefer!

Yes ... I've tried "dabbing" with solder and all that, but sometimes those components are just so small! And it goes without saying that you need to prepare the board as best you can before having a go (and let's be honest, you often only get the one chance) ... wetting the solder pads, cleaning as well (I dare not mention what with, by the sound of things).

Yes, tweezers, poking sticks (needles), and all the rest. Whatever is available. And yes, I like to use liquid flux, as well.

Notice too that I haven't yet mentioned the other part of the fun. Namely, removing the failed component (or the debris that marks where it once was).

Bench mounted magnifiers are great* ... if you're at your bench, that is.

* Expensive, too.

As someone who used to run a pick and place workshop i would recommend this
http://uk.farnell.com/multicore-loctite/96scrp15ags84-25g/solder-paste-96scrp15ags84-25g/dp/1115454

I have removed surface mount processors and replaced them with little more that this stuff a good clean soldering iron and a magnifying glass.(and some solder braid- just incase!)

I have stopped using RS online as it never finds stuff that you know for a fact they supply!

A bit pricey, though, Mate.

I shall need to be on the lookout for an alternative.

OK ... here we go!

There are plenty of tutorials on YouTube if anyone needs them.

The price is out weighed by the ease of use and not damaging components, you can use it more than once too(needs to be kept in fridge)

So what's the resistance of nose bogies? Even a cooked one's at that!

You shouldn't really need anything to hold the components down, except for perhaps these extra fine point tweezers, if you don't watch out anything you use to hold components down usually ends up messy. You'll just have to practice more.

As for removing components you'll also find that for small components you can float them off the pads if you add more solder. I've also used one of these very easy but then again expensive.

It looks like we're all agreed, then. SMD circuit board repairs are worth having a go at, if only for the practice!

But you need a decent set of appropriate tools, and various other bits and pieces if you're to have any hope of success.

Plus, of course (and this hasn't been mentioned yet) availability of the components that need to be replaced. And these are sometimes (often?) hard to identify, let alone source.

Meanwhile, RS 567-581 looks interesting. As does the stuff available from MR. Good word, that:- "Chipbonder".

But eBay also beckons!

and the other thing you need is a steady hand, so that counts me out, hands of a neuro surgeon, no way

That's what too much "wine" does for you, Mate. Not to mention coffee.

Try bananas ... they should calm you down a bit!