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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."
I have a feeling that this is the case with many Abit motherboards. I have been the proud failure of two electrolyte leaking boards.
http://slashdot.org/article.pl?sid=02/11/04/175121 0&mode=flat
In the early 90s some "clever" manufacturer made a line of 486 mainboards with n Kbytes of "Virtual Cache" on board. The cache memory chips were fake, just empty plastic chips soldered to the board. The BIOS was also hacked to show an unexisting cache and of course soldered to the board to discourage analysis/reprogramming.
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.
and they don't last even that! :D
seriously though, this has been a known problem for some time now(6+ months maybe more), it took quite a time to get to slashdot and i wouldnt be surprised if this story is a dupe at some level at least.
world was created 5 seconds before this post as it is.
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.
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
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've got a bad attitude and karma to burn. Go ahead. Mod me down.
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.
I don't keep a lid on my coffee so when I walk around I look busy -me
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
Quidquid latine dictum sit altum viditur
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.)
What's this Submit thingy do?
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!)
www.eFax.com are spammers
You're correct regarding ripple current being irregularities in the power supply current. It's not rare, however. It's part of the internal design of the power supply.
The simplest power supplies work by taking an external AC power source, running it through a step-down transformer(changes the peak voltage to the appropriate level), running it through a bridge rectifier(makes it into pulsing DC), and then using a large capacitor to smooth it into normal DC.
Switching power supplies are a bit more complex, but are based on the same principles.
Unfortunately, the filtering capacitor can take out a large fraction of the ripple, depending on the Thevinin resistance and reactance of the circuit drawing power and the size of the capacitor used for the filtering...
What's this Submit thingy do?
It's a pretty simple fix though. Pull the ECU, remove the dead caps, clean board really well, $2 worth of good quality caps from Digikey and back in business. You can find detailed instructions on how to fix it here
Beauty is in the eye of the beerholder.
We have replaced 25 Gateway E-3400 733Mhz motherboards. This is about half of the number that we have of this particular motherboard and model. Several capacitors are bulged and black stuff is leaking out the top of all these. We have several other models and speeds of the same model but it only is affecting these 733's of a certain age.
The USAF had, in the 1970s and 1980s, a field electronics reliability assessment program. About 1% of the electronics boxes in Air Force inventory were marked with a stencil that said "If this unit fails, send it back to ... for analysis." An Air Force unit tore the failed components apart and found out what went failed. And why. Components were pulled apart and examined in detail, using electron microscopes and other analysis tools to figure out exactly why the thing failed.
When the USAF found something, articles would appear in Aviation Week and other trade magazines, with company names, part numbers, pictures of failed components, and detailed explainations of exactly how the manufacturer had screwed up. This was very effective in tightening up quality control. It is, in fact, one of the main reasons minor components are far more reliable than they used to be.
This stopped during the Reagan years.
In the heyday of 3.5" diskettes, Sony had a unit in Japan analyzing failed diskettes sent in for warranty replacement. They discovered that the main cause of failure was scrapings from the shutter getting onto the recording surface. A redesign of the shutter cut failures way down.
In general, I think there is way too much emphasis on high performance and low cost these days, with nowhere near enough emphasis on stability and quality. This capacitor issue is just one symptom of quality generally going down the toilet.
Over the past year, I've personally had three motherboards become unstable or fail outright due to "exploding capacitor syndrome". The three boards were all different brands (MSI, Abit, and FIC). On the MSI, several of the capacitors literally exploded, and the board wouldn't boot any more. The Abit and FIC just went slowly downhill in terms of stability, as the capacitors became bloated and started to leak. I also scavenged a fourth dead board (another MSI with exploded capacitors) from one of my clients, who was throwing it out.
If you've got a little experience with soldering, it's not too difficult to replace the caps; this will generally restore the board to working order, provided none of the capacitors shorted out and took other components with them when they died. All you need are replacement low ESR capacitors (Panasonic FC series are good, you can mail-order them from places like Digi-Key); a soldering iron and desoldering tool (from your friendly neighborhood Radio Shack); some wire cutters (for trimming the capacitor leads after you've soldered them in place); and a steady hand.
If you get particularly unlucky, you may also have a fried switching regulator (MOSFET), or even burned PCB traces. It may still be possible to salvage the board even in extreme cases like this, but you'll need to buy replacement MOSFETs as well, and get a little creative with soldering some wires to the board to bypass the burned traces.
I've already repaired both MSI boards and the Abit. The MSI from my client turned out to be more trouble than I expected though (one of the VIO regulators was toasted). The FIC is next up on the operating table...
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:
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.