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    Video Card Problems and Capacitors

    Howdy folks!

    I've been reading the Badcaps Forums for awhile now and using the info. to diagnose--and sometimes fix--DOA mobos for myself, friends, and customers. Now I have a new problem. I bought a 'lot' of salvage video cards. Many of them work, which is nice, but quite a few do not, which I expected, and the cause, methinks, is capacitors for many of them. With the defective units, some will simply refuse to pass on a video signal while others will, but the signal will be obviously garbled in some manner or another (staticy images, funky multi-colored images, etc.).

    I've concluded that it is capacitors for a few reasons: for some it is obvious, they are missing a capacitor, one or more are broken, or something like that. For others, it is apparent that the capacitors are starting to bulge, sometimes alot, sometimes a little, but it looks like failure nonetheless. And then there are the cards whose capacitors are either fairly old (and, hence, the card is as well) and/or the capacitor look really scraped up, but not yet punctured or destroyed. These are more on the cusp, but I figure that these might have failed due to capacitor issue as well.

    So what am I looking for? Well, first off, I'd like to learn to distinguish, basically, between cards that are likely capacitor failure issues and cards that have failed for other reasons (I wouldn't mind learning about other video card causes of death either). I can easily replace capacitors, but a card that was simply manufactured incorrectly is probably a lost cause. Any help?

    Second, once I can more accurately diagnose the card issues, I'd like to find a good source for capacitors for video cards. While Badcaps seems to be a fantastic source for mobo capacitors, I don't think I've seen many of the type of capacitors (e.g- 470microfarads, 16volts) that I'd need for a video card here. Any ideas?

    For the moment, these are really my two goals. I've done a little hunting and pecking, but any help that can be offered will be greatly appreciated!

    -Aaron

    #2
    Re: Video Card Problems and Capacitors

    For diagnosing, consider to buy an ESR meter, wich makes it easy to determin if an cap is ok or not.

    For many vid cards you need probably some OSCON caps to, as most cards are desinged for them. Some manufacturer decided later to go better with cheaper Al caps, wich is not always a proper replacement.
    All those caps you need, are either from e.g Farnell or Digikey aviliable, or from waifong.hk. They usually have some ocsons too.

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      #3
      Re: Video Card Problems and Capacitors

      Hey Gonzo, thanks! I took a look around for places to buy an ESR meter, but I was wondering if there was a particular meter and/or store you'd recommend? There seem to be some real differences between them.

      Thanks for the heads up on the OSCONs, I'll check into getting some of those, although do those tend to fail? I've had to rely on eye inspection up till now, which isn't always bad, but is hardly definitive. Still, I don't recall ever running into an OSCON that looked suspicious.

      The AI caps, those I'm not familiar with, can you please describe which are those? Are they the ones with three prongs coming out of the bottom of what looks like a small piece of black plastic? I've always wondered about that one but I never bothered to check it out.

      Thanks again,
      Aaron

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        #4
        Re: Video Card Problems and Capacitors

        I suggest no particular ESR meter, but those Parker desing meteres are cheap and sufficient. In Germany there is a company "ELV.de" wich are seling an DIY kit for an ESR meter with LCD display.
        Do a search here, some mebers here have experience with ESR meters.

        In generall, those Oscon caps aren't getting bad. But there are some Solid polymer caps from other brands, wich certainely fail.
        I meant those oscon as an endurable replacement. And some manufacturer tend to replace the Oscon caps with normal aluminium-elektrolytic (AL caps) ones. This is generally ok, but the caps must be of a good brand and mutch larger in capacitance then the Solid-polymer ones. The most stressful place is the input of the voltage regulator (VRM) (e.g the 12v from the molex or the 1.5v from the Bus) and normaly those solid -polymer caps are used there.

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