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Beware the leaky capacitors

In case you haven’t heard about it elsewhere, there are some recent motherboards having problems with leaky capacitors.

Basically, the problem is the electrolyte in the capacitors becomes chemically unstable, the capacitor pops and starts leaking, the capacitor stops doing its job, and system stability falls out of the sky.

An EE can do a better job of explaining what a capacitor does, but in my very limited electronics background, every project I ever did used capacitors to eliminate noise or smooth out current.

Abit has come out and acknowledged the problem, but other manufacturers are also said to be affected, including Asus. So this isn’t a problem limited to cut-rate boards, although it wouldn’t surprise me if the cut-rate boards also are affected, because the issue stems from cheap Taiwanese knockoffs of a costlier Japanese design.

Identifying problem boards can be difficult, because the affected caps generally are unlabeled, but not all unlabeled caps are problematic. And, as you can see, my usual advice of sticking with a big-brand motherboard doesn’t save you in this case.

I recall a few years ago an article on one of the newsy tech sites like Cnet or ZDNet said some older models of Soyo motherboards could develop this problem. At the time, Soyo declined to comment. So this isn’t exactly a new problem. If anything, it seems to be cyclical.

If you do have a board that develops the problem, you can probably get it replaced under warranty. If not, a skilled technician can de-solder the bad caps and replace them with higher-quality ones. One technician who performs the service charges $50, which seems very fair to me for de-soldering and re-soldering 28 connections.

It’s definitely not a good first electronics project to try yourself though. If it’s something you want to learn how to do, practice on an old, obsolete motherboard or modem or sound card first. And, naturally, I won’t claim any responsibility.

If you develop the problem, this could also be the excuse you’ve been looking for to upgrade, seeing as it’s getting easy to find new motherboards for $60 or so.

You can read more about it in this IEEE Spectrum article.

7 thoughts on “Beware the leaky capacitors”

  1. A capacitor is a passive component that stores energy. It does this by separating two conductive plates with an insulator. The larger the area of the plates, the more energy you can store (A very simple explanation).

    Large caps are almost always found around components that draw high currents (like on motherboards) for reasons such as making sure that if any component all of a sudden draws a larger amount of current then the capacitor will compensate with its stored energy so that a dip in the current delivery won’t happen. Switched powersupplies (like the ones we got in computers) are very bad at responding to fast current changes so caps are used to “fill in” when the need arises. That is just one use, there are several uses of course but the big caps on the motherboards in question are most probably that type of capacitors.

    A word on soldering. You bring up a very good point Dave, doing this type of work on something like a motherboard is bound to fail if you haven’t had practice. You need to have the right type of soldering iron with the right temperature and you got to know your solder as well. There are two things that can happen to someone who is new to soldering:

    1. The person in question heats up the solder point too much which results in the copper thread on the board loosening up or breaking off. It can be fixed, but a good fix can only be done by someone who is experienced.

    2. The person manages to get the old capacitor out and while soldering in the new, the heat from the soldering iron isn’t distributed well enaugh to all parts that are supposed to connect together which results in a “cold” soldering point (sorry, English is not my first language so I am not sure on this one). What happens is that the soldering point looks fine but underneath it does not connect the connect points, or does so badly which means that a few weeks down the road you start getting strange problems that you can’t locate (because everything is covered with solder).

    There are other issues. Heating the solder too much can be a problem as well and of course, you should also make very sure that you really get the polarity correct. If you solder a capacitor the wrong way then (depending on type) it will most probably explode (loud noise and terrible smell). Make sure your eyes are out of the way when turning on the power for the first time after soldering in new capacitors.

    I should also mention that capacitors get weaker as they grow older. If they are a cheap design or very old then they might loose their capacitance to the point where they fall out of spec and can’t do their duty anymore. Sometimes when older electronics components fail, a change of capacitors might fix the problem. This is one of the reasons why a true audiophile will replace capacitors in his speakers (if they contain passive filters) and in his amps, for the cleanest sound production.

    /Dave T.

  2. Thanks, Dave.

    And in response to your point #2, the terminology I hear most often in U.S. English is “cold solder joint.”

    Which brings up a couple more points. When you’re lucky, you can recognize a cold solder joint by its dull appearance. A good connection tends to be shiny. But the second point is just as important: Not everyone is lucky.

  3. I used to see this problem on Mac II motherboards all the time. The first problem wasn’t the capacitor failing to work or falling too far out of spec — it was the contents of the capacitor all over the traces below it causing problems. A spray of Tun-o-wash covered a multitude of sins and sometimes gave those boards another several months or even a year or two of extra life before the capacitors themselves quit working the way they were supposed to work.

    I imagine today’s motherboards would be a lot pickier about such things, and more susceptible to failures or actual harm, than those 15-year-old Macintosh systems were.

  4. I’ve actually done resoldering on the boards, and was successful (but I do have a background in electronics). The cold solder joint is very much an issue.

    If you’re going to do it yourself, you really need the right tools. The Radio Shack el-cheapo specials won’t cut it. Safety glasses, as well. Wear them. They work better that way.

    With the low cost of mobos nowadays, though, it’s worthwhile to just have another motherboard lieing around. One thing I have been considering on these has been a ‘cup’ around the capacitor – open. kind of \_/ in shape, so that there is cooling to the capacitor – but if the capacitor blows, the motherboard is protected and the leakage is directed away from the motherboard, and any cards nearby. One could even have a gravity catch at the lower side. I’ve seen bad capacitors spray on RAM, on modems… it’s a nasty business when a bad capacitor can set you back an entire system.

    BTW… if nobody ever thought of that cup like thing around the the capacitor, and never published anything on it, then I am doing a GPL on it right here, right now… ๐Ÿ˜€ Go forth, use it in good health. I hope it works ๐Ÿ˜ฎ

  5. Make sure you file a patent on that idea. Then when someone else patents it, you can tell them they’re violating the GPL and sue ’em. Then you can use the money to buy Gobe and GPL the software. Hey, I like this… ๐Ÿ™‚

  6. Well – per an email discussion with Richard Stallman – I don’t need to patent an idea like this – as long as it’s *published*, which it now is. Now nobody can patent it (if it’s not already patented!).

    Of course, I should probably not take the chance, and publish it elsewhere…

    I don’t know that I would want to charge for the idea. I think that it would increase the cost of motherboards, and therefore adversely affect the consumer – when all I am trying to do is save them a dollar.

    Dumb, probably. A few years ago I would have rallied… but I really don’t see how charging people more money will help.

    All of this could be avoided if mobo manufacturers used better capacitors probably – and the price offset would be the same. ๐Ÿ˜ฎ

    Makes no sense. Probably why you don’t see the cups on the capacitors.

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