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    #1

    Video Card Issues

    So, a family member is running an older PC that I put together mostly from spare or cheap parts, about three years ago.

    -AMD Athlon 64X2 4200+ CPU
    -2GB (2x1GB) Kingston RAM*
    -MSI HP MicroATX Motherboard from dx2250
    -Asus MicroATX Case
    -FSP ATX-300PA Power Supply*
    -250GB Seagate SATA HDD

    *denotes parts that were new, at the time.

    It's running a ___ copy of Win7 Ultimate 32-bit.

    Anyway, yesterday I got an nVidia Quadro 1700 card for it. That's a PCI-Express video card with two DVI ports. They upgraded from a single 19" 1280x1040 Samsung LCD to two Dell IN2020M monitors i gave them. the video card was because I didn't want to use VGA, and also because the onboard graphics not only suck but only have a single VGA and no other monitor connection.

    I put in the card, turned it on, no problem. Started downloading driver for the video card, went into the other room to set up the Chromecast I gave them (hey, I didn't need it!)... I come back, and the computer is dead. If I unplug it, wait a little while, plug it back in, press the power button, I get a twitch, then it's dead.

    At this point I took it home, assuming it was the power supply. Put in a partially re-capped Antec True 380W, put the case side on (I didn't think I'd need to do any more work). Turned it on, fans, hard drive, etc. go on. Great! But no monitor output. Then I smell burnt electronics and see smoke coming out of the computer. Not a lot, but a little bit.

    So, I took out the video card, using VGA onboard on a single monitor works fine.

    I'm assuming that the original power supply is fine (my handheld PSU tester says it is) and that it had SCP while the Antec didn't, thus further damaging the video card that failed? But none of that makes any sense.

    Why would that happen??
    Tags: None
    #2
    Re: Video Card Issues

    Shorted MOSFETs on the vid card, likely from bad caps. There's at least one buck converter on that card.

    If the high side FET shorts, it will put the incoming supply (12V?) straight into the GPU. Sometimes, the controller is able to turn the lower FET on and short the overvoltage to GND, like a CPU reg, but don't count on it.

    The two MOSFETs will have holes in them. Possibly the GPU, depending on above, and the VRAM, unless fed from another converter.

    Sacon FZ strikes again?
    "pokemon go... to hell!"

    EOL it...
    Originally posted by shango066
    All style and no substance.
    Originally posted by smashstuff30
    guilty,guilty,guilty,guilty!
    guilty of being cheap-made!

    Comment

      #3
      Re: Video Card Issues

      It's a G84 chip aka 8600GT. All of those were faulty from the get go, so no wonder it crapped out when you installed the driver. Though they normally just fail with no video and don't short out, you may have stumbled upon one where the GPU went short.

      Another possibility, which has more odds of repair, is that for whatever reason, the VRM on the card shorted out. Fixable, but the MOSFETs can be a pain in the ass to unsolder.
      Originally posted by PeteS in CA
      Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
      A working TV? How boring!

      Comment

        #4
        Re: Video Card Issues

        Well, it's hard to tell because the case was closed so I coudln't really see where the smoke came from... but it smells more on the end not the chip I guess? Not sure what I'm saying at this point.

        The card is all solid caps/good caps.

        Comment

          #5
          Re: Video Card Issues

          I see two switchers and possibly one linear reg there. Check those MOSFETs for shorts...

          Originally posted by Th3_uN1Qu3 View Post
          It's a G84 chip aka 8600GT. All of those were faulty from the get go,
          Heehee... that hit me right between the eyes, didn't even notice...

          Originally posted by Th3_uN1Qu3 View Post
          so no wonder it crapped out when you installed the driver.
          Heat = expansion = breaks/shorts.

          Originally posted by Th3_uN1Qu3 View Post
          Though they normally just fail with no video and don't short out, you may have stumbled upon one where the GPU went short.
          Which would kill the converter(s).

          Originally posted by Th3_uN1Qu3 View Post
          Another possibility, which has more odds of repair, is that for whatever reason, the VRM on the card shorted out. Fixable, but the MOSFETs can be a pain in the ass to unsolder.
          True, but it's still one of those NVidias.
          Last edited by kaboom; 12-29-2013, 04:57 PM.
          "pokemon go... to hell!"

          EOL it...
          Originally posted by shango066
          All style and no substance.
          Originally posted by smashstuff30
          guilty,guilty,guilty,guilty!
          guilty of being cheap-made!

          Comment

            #6
            Re: Video Card Issues

            I've replaced mosfets one various video cards successfully. It's a little tricky to pull the drain part, but with a good iron and enough heat, all you really need is add a little bit of solder and gently pull it up. Then the gate and source pads can be removed very easily. Time to pull out the multimeter and look for shorts or total absence of current in all the mosfets. But if one burnt, it should be clearly visible.
            You'd want to have some dead motherboards and video cards to get some spare mosfets.

            Comment

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