"Pirate" electrolytic caps - identifying?

I'm trying to analyze a group of almost simultaneous failures in products that were released in 2002. The product is built on an x86 motherboard, in a housing that meets or exceeds normal PC-case airflow. It SEEMS - and I'm still burning in a "repaired" board to test this theory - that the culprit parts are specific electrolytic caps used in various places over the PCB.

The caps in question are G-LUXON 1000uF, 6.3V, 105 deg C rating, date code 0117(M). ALL of them are visibly bulged on top. Sticky dust-mud has gathered in the intersection of the score-marks on top, which leads me to believe that they bulged enough to break the can here and electrolyte has vented out. All the other electros on the board look normal. But then none of the other caps on the board are G-LUXON brand; they are mostly Sanyo.

I'm wondering if this is a symptom of that problem people were talking about a while ago, where an incomplete/not-ready-for-primetime electrolyte formula was stolen and used in Chinese-made caps, which then exhibited an unusually high mortality rate.

Reply to
Lewin A.R.W. Edwards
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Almost certainly. Luxon was reportedly one of the companies (Taiwanese) which purchased the bargain-priced (but defective) electrolyte from Luminous Electric in China.

I had a pair of Apple Airport base stations go bad as the result of failed Luxon 'lytics. Neither had yet leaked, but both were bulging badly and had gone high-ESR. Replacement with another brand fixed the problem.

You can probably expect most of the products built with the defective capacitors to fail, after a few hundred to a few thousand hours of operation, as the caps electrolyze away their electrolyte. As far as I know, replacement of the defective caps is the only preventive or curative measure.

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Dave Platt                                    AE6EO
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Reply to
Dave Platt

FWIW, Luxon (Taiwan based, but undoubtedly with China manufacturing) has denied involvment in that scandal.

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Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

Seems strange that they all went south, is it not also possible that the board had an on-board regulator failure??

Just a thought.

Peter

Reply to
Peter A Forbes

And Clinton didnt inhale. Pale of broken caps from Abit boards knows better.

Pozdrawiam.

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RusH   //
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RusH

It doesn't seem very likely. These caps smooth a 3.3V rail which runs all over the board. There is a group of four of these caps near the processor, and one near the RAM slots. Near a couple of other subassemblies, there are smaller (330uF 6.3V) caps on the same rail. These other caps are visually fine, and I pulled and tested a few at random and found them close to nominal value. It's just the G-LUXON

1000uF caps that are bad. Most of them measure 5-10uF or open circuit.
Reply to
Lewin A.R.W. Edwards

The runtime clocks on the failed units are, interestingly enough, clustered around an average of approx. 3,400 hours. Without looking through them all, I see the lowest at hand is 2171 and the highest is

3709.

Well, this is good and bad news, assuming that is in fact the only problem. It's good news in that the customer obstinately selected these particular boards instead of a more expensive board I had originally recommended ;). It's bad news in that I think I'll be asked to repair them all rather than testing and requalifying some new motherboard.

One of those "quick" contracts that rears up a couple of years later to bite one's hindquarters. Oh well. Thanks for the reply. I hope the one I repaired is still running on Wednesday, because if so I think the problem's fixed (it usually shows up within an hour of powerup after cold, I figure a few days trouble-free is fairly safe).

Reply to
Lewin A.R.W. Edwards

On Sun, 31 Oct 2004 18:50:57 +0000 (UTC), the renowned Peter A Forbes wrote: f

If one goes high ESR, it increases the power dissipation in the remaining good caps.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

It's because the defective electrolyte produced gas at a consistent rate.

Of course, it's likely that a regulator failure would fry the board BECAUSE the capacitors failed.

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Dave Farrance
Reply to
Dave Farrance

Dave Farrance wrote in news: snipped-for-privacy@4ax.com:

They are usually used as the filters on a switching power supply.

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Reply to
me

In comp.arch.embedded Lewin A.R.W. Edwards wrote: : > >The caps in question are G-LUXON 1000uF, 6.3V, 105 deg C rating, date : > >code 0117(M). ALL of them are visibly bulged on top. Sticky dust-mud : > : > Seems strange that they all went south, is it not also possible that the board : > had an on-board regulator failure??

: It doesn't seem very likely. These caps smooth a 3.3V rail which runs : all over the board. There is a group of four of these caps near the : processor, and one near the RAM slots. Near a couple of other : subassemblies, there are smaller (330uF 6.3V) caps on the same rail. : These other caps are visually fine, and I pulled and tested a few at : random and found them close to nominal value. It's just the G-LUXON : 1000uF caps that are bad. Most of them measure 5-10uF or open circuit.

Are you sure you didn't touch the ripple current specs of the caps? I guess, near the processor and the switching regulator the caps will carry a substantial ripple current.

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Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

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Reply to
Uwe Bonnes

For your pleasure and enjoyment, an excerpt from an old comp.risks digest:

--- Begin Included File ---

------------------------------

Date: Tue, 20 May 2003 16:44:19 -0400 From: "Jay R. Ashworth" Subject: The Great Capacitor Scare of 2003

In RISKS-19.13, Mich Kabay quoted the *EE Times* on "The Great Capacitor Scare Of 1997". People were building motherboards without enough power supply filter caps, it seems, and machines were locking up.

Oh, to have problems that minor again...

The Great Capacitor Scare of 2003 is going to be *much* worse.

It seems, according to several news stories (linked at the end) that a materials chemist who worked for a Japanese company, Rubycon Corporation -- which manufactured electrolyte for electrolytic (! :-) capacitors -- left his employ, and ended up working for a Chinese capacitor maker, Luminous Town Electric. (These names tend to sound quaintly amusing to USAdian ears, which might not be accidental...) Apparently, in a fairly clear case of corporate espionage, the fellow's cow-orkers then "defected with the formula" (PCN says, in a confusing bit; defected to where he was?), and began to sell the electrolyte to many Taiwanese capacitor makers.

Alas, there was one small problem.

The formula wasn't *complete*. The capacitors, which ought to have been good (in some cases) for up to 4000 hours, were failing in half that -- or, if you believe Intel, in as little as 250 hours. The electrolyte apparently outgasses hydrogen, and pops the seals on the cap, leaking electrolyte onto the board. The missing ingredient was the one which prevented this. I'd speculate that this might not be a point-catastrophic failure... these caps might pop and leak out slowly, shorting out circuits.

But it's even worse.

The Inquirer may put it best: "It is not currently known how many market segments may have been affected by these poor parts, which can be found in motherboards, switchmode power supplies, modems and other PC boards. The failures of the aluminum capacitors might just be the 'tip of the iceberg,' says Zogbi. "Other component failures from low-cost Asian suppliers might be forthcoming," he warns.

"Around 30 per cent of the world's supply of aluminum capacitors is manufactured in Taiwan, according to the Paumanok Group. Confusion over which manufacturers may have used the faulty electrolyte is sending buyers back to Japan to source their capacitors. The extent of the problem in product that has already shipped won't become clear until components start failing, which may not happen until halfway through the products' life expectancy. "

But even *that* may understate the problem...

How many electronic products do *you* know of that use electrolytic capacitors? The RISKS are so obvious that I don't even have to say "The RISKS are obvious". [But you did anyway! PGN]

*The Inquirer* coverage is at
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*Passive Component News* is at

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Check out the tenor of the editorial footnote; it's as classic as it is uncommon.

TTI, who bill themselves as "The world's leading distributor of Passive, Interconnect, and Electromechanical components" have put up an entire page tracking press coverage of the issue:

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Jay R. Ashworth, The Suncoast Freenet, Tampa Bay, Florida

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snipped-for-privacy@baylink.com +1 727 647 1274

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I haven't checked to see if the referenced links are still up. FWIW, yours is the first problem regarding these electrolytics (if your problem _is_ these electrolytics) that I've heard about.

Regards,

-=Dave

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Reply to
Dave Hansen

the board

guess,

My thoughts also. If this is indeed a 3.3V line for a power-hungry processor the caps needs to be very low ESR types or many of them in parallel

Cheers

Klaus

Reply to
Klaus Vestergaard Kragelund

Usually *both*.

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

I didn't design the board - it's an off-the-shelf Pentium III motherboard. These systems are due for replacement in a little less than nine months. I figure the new caps ought to last this long, since they previously lasted more than two years.

Reply to
Lewin A.R.W. Edwards

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