Burned out motherboard capacitors after only 22 months

By davexnet ยท 10 replies
Aug 21, 2009
  1. Hello all,
    I originally bought a Biostar Geforce 6100 M9 in October 2006 and a single-core CPU.
    About a year later, I upgraded the CPU to a dual-core AMD64 X2.
    The motherboard would not operate properly with the new CPU, there were issues with
    powering off/on.

    Biostar replaced it for me in October 2007. It's been working fine, quite a bit of use,
    using the onboard video and sound - nothing to stress the system components.

    Yet after only 22 months the capacitors that are lined up against the cpu socket
    (5 of them) are failing. 2 are bulging, and 1 has some brown crap coming out the top.
    I'm amazed the PC is still working.

    Were there some bad capacitors floating around 2 years ago?
    This seems an awfully short life.
  2. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    That particular mobo is known to have a hot-running northbridge, which may be the cause of the failing caps. Also, the caps themselves may be of the Fuhjyyu or OST brands, which are known to fail under hot conditions.

    You can re-cap it pretty easily using the appropriately-rated caps, provided you have the know-how and expertise to do so.
  3. davexnet

    davexnet TS Rookie Topic Starter

    Thanks very much for the info. I may try and re-cap the five in question.
    I emailed Biostar, but so I've got no response. I may try my local electronics shop.
    Probably find higher quality parts there.
  4. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    I would recommend using Japanese caps like Rubycon or Hitachi, if they are available and are decently priced.
  5. davexnet

    davexnet TS Rookie Topic Starter

    Rubycon capacitors obtained; transplanted into the board; so far so good.

    I found the soldering a little tricky. After removing the old caps, the holes
    were blocked with solder. I used a needle (after first snipping off the sharp tip)
    to push through from the top of the board while I was heating it at the back with
    the soldering iron.

    After the holes were cleared it was simple to insert the caps and solder them in.
    I did have a concern though.
    The back of the motherboard where the cap legs stuck through - I'm not sure if during
    the Cap. removal I was a little too rough. First my 25W soldering iron apparently didn't
    provide enough heat. Couldn't melt the solder. So stepped up to the 40W iron and it worked
    OK. Bottom line, by the time I'd finished the holes were a little rough looking and I was
    concerned I'd destroyed the very small area to which the cap legs are soldered to.

    Anyway it's working. Currently using onboard video - nothing in the box yet to draw
    much power except the CPU.
    When I put my 8600GT back in, I'll know if it's fixed. That's how I found the problem
    in the first place. The picture started going wavy and oscillating slightly.
    I guess the video card draws a lot of juice through the mobo. When I took the card out
    and reverted back to the onboard picture was stable again.
  6. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    Destroyed in what sense? As long as there's a good solder joint for the cap to stay in place, you should be just fine.
  7. davexnet

    davexnet TS Rookie Topic Starter

    Hello -
    I once had an experience fixing an old Panasonic TV. I'm no electrical wizard, but I found parts info
    and instructions on the Internet that matched the symptoms exactly.
    When I removed the old parts, the solder-side of the circuit board was destroyed in 2 or 3 places.
    The fine conductive traces had disintergrated close at the solder spot - making it extremely tricky to
    to solder the new parts components into the circuit.

    I ended up improvising. Poked the new parts through the holes, soldered in where I could,
    and using a magnifying glass where the traces had broken down, running a separate wire
    from the leg of the part to where ever it was supposed to go. It was a success, TV still good
    5 years later!

    I thought something similar had happened to the motherboard. The caps seem to be in OK.
    When I wiggle them gently, there's no movement on the solder side.

    I ended up getting the parts from Ebay - a guy in Hong Kong. $6.99 for 6,including shipping.
  8. raybay

    raybay TS Evangelist Posts: 7,241   +10

    Rage 3K Moiz, could you post some basic instructions on how to remove and replace Capacitors... or a source of where one can learn to do that?

    I am sure several people on this forum would benefit.
  9. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    These are good guides I have found:

    Of course, choosing the capacitors correctly is also important. I usually use only Rubycon, Hitachi or Nippon Chemi-Con caps. You have to make sure the voltage ratings and capacitance values match exactly with the caps you are replacing. This is a very crucial step that anyone looking to replace caps must consider.
  10. raybay

    raybay TS Evangelist Posts: 7,241   +10

    Thank you for the prompt, and first class, reply.
  11. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +38

    You're very welcome raybay.
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