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Even Intel used bad capacitors

Discussion in 'Electronic Components' started by Leaking Caps, Jan 12, 2008.

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  1. Leaking Caps

    Leaking Caps Guest

    The motherboard is an Intel D865PERL purchased in October 2004. Two of the
    electrolytic capacitors are bulging and leaking:

    http://i7.tinypic.com/8g6ywx1.jpg
    http://i15.tinypic.com/7x17g5t.jpg

    I can't determine their value and the board is out of warranty anyway. I
    keep reading about solid state capacitors. Are those the same as a "solid
    capacitor"? Instead of a tall can wrapped in plastic, the solid capacitor
    is short and metal, not wrapped in plastic, and doesn't have vent holes.
     
  2. It's written on the other side. Take a few pictures, the camera flash and
    magnification will get you a reading, you just have to find an angle good
    enough to see it.

    It's probably 10V 1000 µF. Panasonic make some good replacements.
    RS Components order code 526-1115, for example. Check the lead spacing,
    they're likely an exact match but maybe not.
     
  3. Eeyore

    Eeyore Guest

    You're looking at the wrong side !

    That's pretty mild bulging and I see no leaking.

    Graham
     
  4. Eeyore

    Eeyore Guest

    Any idea why such caps are very often 10V rated and not 6.3V ?

    Graham
     
  5. Hal Murray

    Hal Murray Guest

    Probably to get the current rating that they need. They probably
    need a bigger package to get rid of the heat and the extra
    voltage comes along with that.
     
  6. Not really sure, but I guess it's a general principle of overrating being
    likely to improve life and performace if it's not significantly more
    expensive. Could argue for lots of stuff like higher ripple current, lower
    ESR, better heat dissipation if the can is bigger, better surge resistance,
    but in the end I doubt they calculate all that, they probably just test with
    one cap, then uprate to the next voltage for production on the grounds that
    it's cheaper if many are the same, and it probably makes less returns.

    In short, crude uprating and using lots of equal parts costs less than trying
    to design their performance to precise limits. Same as it's always easier to
    fligh high and straight than to hug the ground to avoid radar, even though
    the initial cost of getting up there is greater.
     
  7. Leaking Caps

    Leaking Caps Guest

    OK, I took some more pictures and got their value. They are Nichicon
    brand, 560uF 6.3volt. Both of them show signs of oozing an amber liquid
    from the top.

    http://i10.tinypic.com/855aihf.jpg

    The board was stable if I had one piece of memory installed. If I had two
    pieces installed, same brand and part#, I would get random crashes.
     
  8. You could uprate to those 10V 1000µF caps I mentioned. Capacitance tolerance
    alone can change from nominal 560 to 20% more, it's not that critical.
    Adequate supply smoothing to memory modules IS though. So check the lead
    spacings. If they match, get some. Get several tens of them even, they'll
    replace other caps you haven't found yet, probably. Most firms like to stick
    to standard values, so you won't go far wrong buying between 20 and 100 of
    RS's part 526-1115. As far as I know, they only buy from direct sources where
    possible, I've not yet seen any problems with parts bought from them.
    Probably same with Mouser and Digikey, etc, I doubt they'd risk buying from
    loose sourcing that let in counterfeits easily, it would damage them too much
    if that happened.
     
  9. Eeyore

    Eeyore Guest

    One of those is a Nichicon part. I don't recall those being affected by the
    'bad caps' issue so it's probably just simply 'worn out' from extended use.

    Graham
     
  10. Those are Aluminum Electrolytic Capacitors

    http://www.interfacebus.com/Electrolytic_Capacitor_Manufacturers.html

    I haven't heard of this issue for a few years now
     
  11. Eeyore

    Eeyore Guest

  12. Eeyore

    Eeyore Guest

    Yes I'm aware of that but advice I've had from cap makers is that it's completely
    unneccesary. It affects ONLY leakage current and that's largely unimportant.

    Graham
     
  13. Really, there are a number of working engineers that produce designs
    under a mandatory derating. I think mine is 10%. I won't walk into a
    design review with a 6V cap working off a 6 volt line..

    Most of the derating guidelines I provide are from Military standards,
    some maybe from NASA

    http://www.interfacebus.com/
    http://interfacebus.blogspot.com/
     
  14. Eeyore

    Eeyore Guest

    Simply out of prudence neither would I normally but I have the following tale to tell.

    I was designing an audio power amp and to meet the desired power output, the supply
    rails were ~ 67V off-load. That would have ruled out 63V caps for the psu but the
    manager was so concerned about cost that he spoke to the cap makers and asked for their
    advice.

    They repsonded that there would only be a very mild increase in leakage current and
    that the caps were designed for at least a 10% 'overvoltage' anyway.

    So we used 63V caps on a supply that was 67V off-load and we had ZERO reliability
    problems with that. In fact it was one of the most reliable products that the company
    ever made.

    Yes but most kit isn't intended for military or aerospace use. Most deratings are
    historically based AIUI and modern components really don't need it.

    Graham
     

  15. That's why most consumer electronics dies within two years.


    --
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
     
  16. Hal Murray

    Hal Murray Guest

    I'd expect electrolytics to last a lot longer if they are kept cool
    and/or run below rated voltage.
     
  17. I'm just saying that's where I got the data, not what I was designing
    for.

    Cable company called the othet day, wanted me to buy VOIP.

    I told them their service sucks, there was no way I would purchase
    anything.
    But you have not Complained since 2002?

    How many people just move to another product?

    http://www.interfacebus.com/
     
  18. Eeyore

    Eeyore Guest

    No it doesn't.

    Graham
     
  19. Eeyore

    Eeyore Guest

    Correct. that's VITAL

    Utterly WRONG. This is pure myth.

    Graham
     
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