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Please excuse the poor image quality:

electronics

What are the components that I've circled in red?

The ones on the left look whole and solid. The ones on the right have cracked tops, and although this picture doesn't show it, there are small brown threads coming out of the top. Are the cracked ones broken, or is that supposed to happen?

If they ARE broken, is this something I should worry about? This is a video card, and it appears to be fully functional: I'm using it while writing this post.

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Great answers, everybody! Rarely have I learned so much from asking a single question. –  Chris Nielsen Sep 28 '09 at 21:21
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5 Answers 5

up vote 18 down vote accepted

Looks like capacitors. If those are CRACKS on the top, then the answer to your question is HELL YEA.

They may continue to work for a while, but you're on borrowed time.

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And the two at the top of the picture too... –  KFro Sep 28 '09 at 17:04
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They are about to (or have recently) let the magic smoke out... [en.wikipedia.org/wiki/Magic_smoke] If the card is under warranty it should be covered. If not I have had luck re-soldering new capacitors before. Make a note of the lettering on the parts before they become covered with soot. –  Chris Nava Sep 28 '09 at 18:06
    
More specifically there are dielectric capacitors, and this is a common (and designed) failure mode for such devices. –  dmckee Sep 28 '09 at 18:35
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+1 for the enthusiasm! –  Chris Farmer Sep 28 '09 at 19:17
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Low voltage caps are relatively safe, but I still would not use them. I have seen electrical arcs jumping from the top of blow caps in high voltage circuits. Also all capacitors are dielectric. Perhaps the word people were looking for was electrolytic. A gel like insulator is layered between the conductors. Over time this gel can dry out, especially if the cap is not sealed. When exposed to excess voltage, the gel can swell up causing the cap to burst. This can also happen is the gel or conductors are made of poor quality material. –  Jim C Sep 28 '09 at 19:35
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As @satanicpuppy mentioned, these are capacitors, and they are damaged. The question is: what are they for, and why is the card still working?

I am not as good as the people on the "Name That Ware" contests on bunnie's blog, but I can take a guess.

Judging by the fact that this is a video card, and the fact that this seems to be the edge of the video card opposite to the connectors, I would guess the small black chips with three legs and a tab near the capacitors are voltage regulators. The video card takes 12V from the power supply (either via a direct connection or via the motherboard), but the chips it uses cannot run on 12V; they need a much lower voltage. The higher voltage is used here because it has less loss over long distances, but it has to be converted to the lower voltages near the chips which use them. The conversion process generates some electrical noise, some electrical noise might have been picked up over the long wire, and the chip itself causes some noise, which must be prevented from radiating back to the power source (and to the rest of the computer). Filtering this noise out is the job of these capacitors. In fact, some voltage regulators generate a noisy output on purpose and depend on the output capacitor to turn it into a voltage.

The reason it is still working is that the noise is not enough to overhelm the smaller capacitors near the chip, which directly filter its power. However, you lost a big portion of the safety margin, and you might be radiating quite a bit more noise to the rest of the computer, and even to outside it (but the metal case should reduce that one a lot). If you try running a more demanding application, for instance a 3D game, it could crash where before it would not. It could crash in mysterious ways which you would blame Windows for. And, depending on the failure mode, it could damage other pieces of hardware, even ones which do not seem related (after all, everything is connected to the power supply, which is why skimping on the power supply is not a good idea).

You should replace that video card as soon as possible, and check the rest of the computer for damage.

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Are you suggesting that the noise in the system caused the capacitors to become damaged? I'm curious how exactly one might expect those things to be so cracked. I am no electrical engineer, but it seems weird to me to expect them to look like with just standard wear. –  Chris Farmer Sep 28 '09 at 19:22
    
@Chris Farmer: no, I am suggesting they being damaged could cause noise in the system. It takes more than mere noise to damage them, after all their purpose is to filter the noise out. However, if they short out (or, in some situations, become open) it can cause more than just letting electrical noise out. –  CesarB Sep 28 '09 at 19:32
    
Thanks... just curious. This is an interesting post. Thanks for the detailed response! –  Chris Farmer Sep 28 '09 at 20:40
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To be a bit more specific they are electrolytic capacitors, which have their vents broke possibly having releasing hydrogen, suggesting that they have failed.

Traditionally "computer-grade" electrolytic capacitors used a liquid electrolytic solution or gel between dielectrics. These are quite susceptible to aging and drying out, particularly when operated in a high (ambient) temperature environment.

Around 2003, several mainstream PC manufacturers accidentally bought bad capacitors from several Taiwanese companie(s), including some companies that forged premium brands.

Several PC motherboard manufacturers have switches to solid electrolytic capacitors to avoid the problems with liquid electrolytic, and the scandal from the flawed formula based knockoff capacitors.

So as others have suggested, the video card is now very prone to likely fail sooner rather than later. To protect the rest of your system, I would recommend replacing the video card (or having it repaired/replaced under warranty) as soon as reasonably possible. I believe the knock-off capacitors are considered a moderate fire/spark risk.

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Sorry, You have bad capacitors. Either buy identical ones and resolder them, replace under warranty if you are still covered, or get a new motherboard.

alt text

The top should be almost flat (with slight indents out embossed sections depending on specification... look at the middle one) but you do not want to see any big bumps such as the first one or any leakage as the last one.

If your pc is of the P4 generation, there were MANY MANY boards that had this problem which lead to a lot of random failures as you are experiencing now. I had this problem frequently after just 6 months of heavy usage.

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Agreed. We had a whole series of Dells from that era, and more than 90% of them had to be RMA'd for swollen capacitors. Those were nothing compared to THESE...I mean, you had to run your finger over the top of them to feel that they were swollen, and even at that point, they were non-functional. –  Satanicpuppy Sep 28 '09 at 19:17
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I second. Those are capacitors. The cracks are an indication that they've gone bad or are about to go bad. My advice would be to remove the video card from the computer.

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