Illicit Leaky Capacitors Killing Motherboards

mcd7756 writes "The IEEE Spectrum magazine has an article about how capacitors made with a stolen formula for the electrolyte are leaking and causing motherboards to fail. Some computer manufacturers are admitting to the problem; others are hiding it."

Comments

Experienced it first hand

[Dystopium]

I have a feeling that this is the case with many Abit motherboards. I have been the proud failure of two electrolyte leaking boards.

Re:Experienced it first hand

[zorglubxx]

Damm, that's it !!

In summer 2000 I got a dual cpu MSI motherboard. I had to get it exchanged a year later because a half a dozen capacitators had bursted their top. At that time it took with it a 256MB SIMM.

Just last week I got the same problem again and had to get my 3rd motherboard (lucky for that 3 year warranty). This time it corrupted my hard disks which had to be rebuilt from backups.

I like that MSI dual processor board but I dont really want to be exchanging it every year and a half.

Deja vu?

[philj]

http://slashdot.org/article.pl?sid=02/11/04/175121 0&mode=flat

Low-ESR caps? A lot of stuff.

[Stormbringer]

Basically anything that uses a switching power supply or a switching voltage regulator is at risk IMO. That covers most consumer and commercial equipment other than stuff that's physically too small to have one of these caps, or that handles only audio/radio.

Re:What board models are affected (curious) ?

[FrostedWheat]

I am just curious if the Asus or Abit motherboards that I own might be affected ??

All the failed capacators seem to be from the company JPCON. On my motherboard (that also failed) they are branded JACKCON.

So if you board has these capacators, I'd keep an eye on them.

Re:Screw home PCs, what else are these components

[twdorris]

It's been well established that the ECUs in the '90-'94 turbo Eclipses and Talons (DSMs) were made with substandard capacitors which would leak after several years causing the exact problems outlined here. Traces on the board would be destroyed and teh things would be left useless.

The difference? Mitsubish *never* acknowledged the problem. They just fixed it under the covers in '95 and never told anyone about it. Nice, huh?

Thomas Dorris

DEFINITELY

[ArcSecond]

I've already lost a MOBO to these leaky capacitors. It really pissed me off, since it wasn't even a year old. And yes, it was an Abit board. I will never cheap out again.

I'm sorry this happened

[The-Perl-CD-Bookshel]

However, I'm glad that this is happening to boards that end up in the hands of tech-savvy individuals that can spot the problem. People who buy ABIT, Asus, etc... boards expect a lot from the product that they recieve and are usuially knowledgeable about the equipment that they run.

I could only imagine if this happened to a major computer company, how it would be swept under the rug (which it may already have been). I see that IBM is named in the article, so at least they are willing to accept the failures. IBM is one of the only computer makers that I trust anymore after the way that they handled their hard drive failure issues. Yes, they tried to fix the problem by changing the uptime specs, but in the end, they got the problem worked out without too much hassle to customers (hardware zealots excluded).

I would like to know if this problem has been documented by any users that aren't using products from the manufacturers listed in the article and their expierence with the equipment, service and support.

Hi-Rel Motherboards Don't Use Electrolytic Caps

[LuxuryYacht]

High-Reliability motherboards don't use electrolytic capacitors for their onboard power supplies anyway. You'll only find these types on the typical built like crap (found in the majority of PC's built today)high volume motherboards. 5000 hour lifetime is what you'll find for typical ratings on low esr and long life electrolytic capacitors. This is only 200 days of continuous use.

High-Rel designs use very low esr tantalum caps. like these T530 Series

Re:You get what you pay for

[mmol_6453]

What's really odd is that bulging and popping electrolytic capacitors usually are caused by applying the wrong polarity to them.

When the capacitor is made, a DC current is put through them to form a crust on the metal surfaces inside the capacitor, which is then used as the dielectric.

When the capacitor is used in a product, you have to apply the same polarity to it, or you'll reverse the chemical reaction and get a DC current flow, which boils the electrolyte. (Thus causing pressure inside, causing a bulge and eventually a pop.)

Ripple = heat

[wowbagger]

The issue with electrolytic capacitors is this:

All capacitors have what is called an equivelent series resistance, or ESR (great: now we have 2 TLAs that are overloaded in context: RMS and ESR... )

The ESR only matters when there is a current flow through the device - a static voltage does not create (much of ) a static current flow - that is rather the definition of a capacitor. So if you are putting a DC voltage across the device all is well.

However, if what you are putting across the device is NOT DC, but rather DC with an AC component on top of it, then there will be a current flow as the capacitor tries to hold the voltage constant (again, that's rather the point).

However, due to the ESR, some of that current will cause heating of the device (power = I*I*R).

In caps with the good electrolytic, nothing much happens. In caps with the bad electrolytic, the electrolytic breaks down into hydrogen and oxygen, as well as boiling into steam. Pressure builds, and eventually the cap leaks. Since the other stuff in the electrolytic is caustic, your PC board traces rot away.

Now, at low ripple currents, this does not happen very fast, and any cap will have a long lifespan. However, as you approach the limit of the cap, the heating becomes the dominant factor, and the cap will cook itself fairly quickly.

That's where that 4000 hours comes from - that is not the cap running with a few tens of milliamps of current ripple across it, that is the cap getting amperes of current rammed down its throat, and running very hot.

That's also why you use tantalum caps wherever possible - tant's don't have an electrolyte, they use a very spongy tantalum slug with lots of surface area. They don't have quite the capacitance per unit volume that electrolytics have, but they don't leak, either. (but they do blow up real good (sic) when you exceed their rated voltage!)

Fixing this yourself: a quick and dirty HOWTO

[F00F]

I opened up my machine sometime in December in order to inspect it for this very problem. Because I'd read in the previous slashdot article that Abit motherboards had experienced this problem, and my motherboard was (is) an Abit KT7-Raid (non -A flavor), I was particularly curious. Sure enough, two capacitors had clearly bulged open and were leaking paste, and three more were on their way towards failing. Interestingly, I hadn't had any observable symptoms whatsoever; I just checked the board on a whim.

I consulted the Abit website, and at the time they required the original 'invoice' from the motherboard if you wanted to have them repair the problem for free. If you have that paperwork, RMA'ing the board should not be too troublesome. I really didn't think I could find my old paperwork for this board. Abit offers to repair motherboards without original invoices for a charge of (as I recall) $25.00US. I think you have to pay shipping one way.

I considered using the services of the guy linked to in the previous slashdot article, but his prices were about in line with Abit's. That didn't really help any -- for the amount of money he wanted, I could just have just had Abit do it. I could also have just as easily replaced the board for $45.00 plus shipping on Ebay, but it probably would have just failed all over again.

I felt I could replace the capacitors myself, and as it turns out, I was right. Here's my advice to anyone who wants to try to do this repair themselves:

• Obtain a temperature-controlled soldering iron with a nice pointy tip. I used a Weller brand iron. You can get away with a constant-power iron if you're good, careful, lucky, or some combination thereof.
• Obtain either a solder sucker that you're comfortable using, or the desoldering braided copper wick that's sold for this purpose. My experience was that the solder paste that's used on these PWBs does not wick well. It certainly doesn't wick the way a higher quality silver solder wicks. I got by anyway, but it was a bit ugly at times.
• It is helpful to have a lighted magnifying lens, a pair of small pliers, some good solder, and a circuit board holding jig. You can get away with less. I didn't use a jig.
• It goes (almost) without saying that you should by now have removed all the easily-removable goodies from the motherboard (RAM, CPU, etc.), and that the motherboard should be fully removed from its case. You should give some thought to static control and ESD, of course.
• My board had three through-holes for each capacitor, only two of which were occupied by the capacitor's leads. I suspect this is for interchangeability of capacitor models.
• Obtain good new capacitors. I had to search for 'Low-ESR 2200 microfarad 6V radial electrolytics'. A higher voltage rating is fine, even recommended, but can increase the physical size. I went with 10V-rated capacitors, which were a touch large, but workable. The capacitors I found were rated to 85 degrees Celsius, but 105's are available (and also recommended). I advise against replacing the capacitors with anything other than the previous capacitance rating, although you could probably get away with it. Some caps are rated as 'computer-grade' or some such. This is generally good. Digikey offered good capacitors for $3.00 apiece in small quantities. I found a small shop in southern California near where I live which charged 65 cents apiece. Radio Shack and Fry's are unlikely to have acceptable parts in stock, even if either carries them.
• An iron temperature around 790 degrees Fahrenheit worked well for me. Conversion to Kelvin is left as an exercise for the reader.
• The power capacitors on my board were a fair distance away from any delicate CPU traces. That helped ease my conscience a bit. Hopefully, yours will be too.
• Using the hot iron and desoldering braid, gently remove as much solder as you can from the underside of the capacitor leads, starting on the back face (non-component side) of the board. Remove the capacitors from the board, and thread the leads of the new ones through the exposed holes. POLARITY MATTERS! There is likely to be a polarity indicator on your capacitors, you should match the current polarity (assuming your board manufacturer didn't screw that up, too. Some have.) The polarity indicator typically looks like a painted stripe along one edge of the cap, indicating that the outermost radial lead is (conventional) negative/ground.
• Solder on the new capacitors, making sure to deposit a nice, adequate but not excessive volume of solder. Make sure not to leave a cold (badly-formed) solder joint. Make sure that there's little play in the capacitor afterwards, but that the leads aren't straining their joints.

Good luck. Don't blame me if you scew something up, burn something out, or get someone killed. Send it back to the manufacturer if you're not up to the task, or don't have much experience in such matters. There is a touch to this sort of repair that comes from practice, I think, and the only way to develop it is to get your hands dirty. Or burnt. Or something. Previous to this, I had only a little experience with this sort of rework, so don't be too shy.

Besides, Natalie Portman demands a guy with trained fingers.