By any chance were the capacitors branded "LTEC". If you have a TiVO HR10-250 (the HD DVR that DirecTV distributed) eventually the thing will start reporting an intermittent overheat condition. No, its not actually over temp, intstead one or both of the power supply capacitors that are filtering the 5v supply will have the self-same domed top.
Its happened to me on two of them, and if you peruse the Ebay listings of ones offered for parts, you will be sure to find one or two on offer that are also suffering the same problem. A little time with a soldering iron, and some replacements with a higher temperature rating, and they are fine.
I did notice that the replacement units I bought were noticeably larger than the originals, it was a bit of a squeeze getting them in. They are located inside an inverted U formed by two of the heat sinks. They even have one of them in contact with the to-220 case of a switch transistor, and covered with a big blob of glue, that I am sure helps keep them from cooling (hence my grabbing the highest temp spec I could find).
Because the designer packed them in right next to the hottest components on the board, how much was the fault of the capacitor and how much was just due to years of a bake cycle (they don't have an off switch).
This sounds like a common problem with electronics and I think it must be the components.
I was at the CompUSA warehouse (my son and I go there often). We are lucky to have this nearby. The store front is like a factory outlet. We were looking at building a server, so I was looking at motherboards. All of them seemed to have a claim that they used Japanese capicators of a certain type. I wondered at this, since most were made in Taiwan. After asking around I found that there had been a rash of failures of motherboards a while back, and the cause was cheap capicators. Sounds like Acer did not get the memo.
Isn't it interesting that something so basic as a capicator (and its placement) can cause so many problems?
This makes me wonder whether the components that failed were counterfeit. Counterfeits can be disguised very well these days. Counterfeit components woud certainly explain the high failure rates Naperlou describes.
Rob, you read my mind. That's exactly Rob, you read my mind. Counterfeit parts are exactly what I was thinking; they are becoming a major problem. This really bothers me especially since I deal a lot with mission critical systems.
Yes, Gsmith120, there's just something about the story -- and the resulting comments -- that rings of counterfeit components. The counterfeits are disguised very well these days and they can show up even in non-gray markets in the form of returns.
Rob Spiegel wrote: "This makes me wonder whether the components that failed were counterfeit."
Not counterfeits. The following is from an IEEE Spectrum article published around 2003 describing events that happened in around 2000, as I recall it. A Chinese engineer was working at a Japanese capacitor manufacturer, stole the secret formula for the electrolyte in electrolytic capacitors and started a factory in China. A second engineer, working at the Chinese factory, stole the formula and opened a second factory and underbid everyone else on capacitors.
However, in one of the transfers, some of the ingredients were omitted from the formula. There didn't seem to be any reason for their inclusion and the capacitors seemed to test just as well without them. Unfortunately, one of the ingredients was a stabilizer which prevented aging and degradation of the electrolyte.
These bad capacitors got into all kinds of electronics-- VCRs, TVs, computer motherboards, and monitors. Nearly all the computer motherboards failed, about 24 months out. The problem manifested itself in failures to boot, reboots in mid-stream, hangs, and crashes. All of the manufacturers but one refused to fix or replace the failed computers, in spite of the clearly inferior parts, arguing that they were out of warranty. Only IBM replaced every one. In fact, if you were having difficulty replacing the motherboard, they would send a suit-and-tie customer engineer to your house to do the job.
The stolen formula story makes for a good movie, but it's not likely true. In 2004, I met the chemist who had DELIBERATELY altered the electrolyte formula to reduce the ESR so as to produce a marketing point for cutting into the Japanese market share. The Wikipedia article "Capacitor Plague" now has some nice (if you're in the failure business) photos of the results.
For those who are really curious, there's a wiki article, which has more detailed technical info than you'll want to know, including a detailed chemical analysis: http://en.wikipedia.org/wiki/Capacitor_plague
Those who say this may just be a quality issue, as opposed to a deliberate design choice, may be on to something. I talked to a manufacturer today (who shall go nameless). He told me he visited 400 Chinese and Taiwanese manufacturing facilities over four months, in search of a supplier. He claimed that only four of the 400 met his quality specs.
That's a surprising piece of news, Chuck. I was under the impression that manufacturing in China was improving. I've heard that some plants in China were matching or surpassing U.S. plants. Aparently those plants are in the minority.
No, the electrolyte does not age; it attacks the dielectric and the underlying metal. It starts doing so as soon as the capacitor is assembled (which accounts for the negative time parameter in the Weibull plots -- most people start the clock when a voltage is first applied across the part). There are now some nice photos of the effects of the chemistry in the Wikipedia "Capacitor Plague" article.
Again, this "stolen formula" story is poular (and widespread -- multiple places and multiple times), but unintended consequences are way more likely.
Here we are again, discussing a subject that comes up on our website almost on a daily basis. I'm amazed that the cost of a few capacitors is worth the damage it causes to Acer's reputation. If there are websites dedicated to problems like these, the situation must be pretty bad.
The same exact issue happened to me with TWO Samsung LCD televisions! I have a large LCD TV in my living room, and it started to take minutes, instead of seconds, to turn on. This wasn't too big of an issue until it started to take upwards of 15 minutes. I did some research and found that the power supply capacitors would blow (four of them). I replaced them and all was well.
One year later, the small TV in another room began to show the same problem! I immediately tore it apart and found the caps on the power supply bulged. I am a mechanical engineer, so it was quite interesting for me to fix this (thanks to the internet). The toughest part, especially on the small TV, was fitting the larger caps into the small space.
It always boils down to money and bad days at the factory.
I don't think I have ever replaced a Nichicon in 20 years. When I find a bad part, I always go looking for other parts of the same value. Nearly always they are bad too. Since manufacturers buy in bulk lots, a bad day at the cap factory is a bad day for the end user.
Umm, it's not a cost thing; it's a performance thing. The destructive electrolyte produces a much lower than normal ESR, and if you wait a bit, it also produces a much higher than normal capacitance for the size of the part (the already mentioned photo of a small capacitor in a larger capacitor -- physically and electrically -- shell comes to mind). Why would a design engineer choose a known-good part with higher ESR and larger form factor? Especially when accelerated testing (acceleration of the NORMAL failure mechanism) shows that the lifetime of the part is still many times the required mission life. It was only testing to failure (frequently done by consumers) that demonstrated that there was a new failure mechanism in play, and the standard accelerated testing is terminated way before failure.
On a previous job, I worked in the technical department of a importer of LCD TV's and computer monitors. The computer monitor product line was manufactured by a well known Taiwan OEM manufacturer with good reputation and big name clients, and branded with our company logo. Technical documentation, EMC test and product samples - everything was perfectly fine. After 8 months and truckloads of monitors already sold, the number of field returns started to rise. In the summer, it became a deluge; almost every single monitor broke on the field. The power supply had faulty capXon electrolytic capacitors. On closer examination, the power supply design turned out to be questionable. The faulty capacitors were extremely close to heat spreaders, and they produced high amount of heat themselves. They may have worked well in a traditional full bridge power supply, but certainly not in a high-frequency switched mode power supply. A comparison to the schematic diagram of the switched mode controller chip revealed that the power supply manufacturer removed all the current limiting components except the main safety fuse, and substituted a 1000V rectifier diode with a 200V rectifier. The result: a minor power surge or the increased load caused by the degrading capacitors would open the safety fuse. This was supposedly a quality product from a reputable supplier. The company management was so upset that completely abandoned this market and closed down the business unit. The last container full of soon-to-be broken monitors was sold at scrap price to a broker that shipped them to central Africa. We enclosed a courtesy gift: a box full of quality replacement capacitors and complete instructions for the rework. I keeped for internal company use about 50 monitors. After replacing the capacitors, they still work after almost 5 years.
I like the idea of the care package for the end user. I once purchased a DIY bookshelf that contained two hardware kits and a note that read to only use the one specially marked hardware package because the screws were a better design. The rework for the faulty screws was open the box and add a new bag and a note then retape the box and hope for the best.
Another thing nobody mentioned is internal heating of the capacitor. Caps have a parameter called equivalent series resistance (ESR), which varies with frequency. High ripple current applications (e.g. output caps on a switching power converter) require special attention to ESR. Ripple current applied through the ESR causes heating...specifically, P= i*i*ESR.
I can see a bright but inexperienced engineer noticing two different 100uF caps on a BOM...five pricey and 20 cheap. Logical thing to do is make all 25 the cheap version, saving a few cents in component cost and removing a "duplicate" line item from the BOM. Seems like a great solution until the manufacturer gets a flood of returns 2 years later, realizes ESR was overlooked and the costlier low-ESR caps were on the BOM for a reason....
I used to catch grief all the time for refusing to mess with someone else's design until I could find sufficient documentation (like a schematic! and some notes would have been nice) to get some idea of why the original engineer picked the parts he did!
Voltage derating is for the normal failure mechanism. The bulging capacitor failure mechanism is a different mechanism. It is totally chemical and starts as soon as the capacitor is assembled, continuing even if there is no voltage across the capacitor (of course, as with all chemistry, heat accelerates the reaction).
Looks like you did a great job - that is one thing I love about the advent of the internet. It has become a valuable resource for troubleshooting. I have had issues from my video camera to my garage door opener and plugging in the problem has brought not only answers, but video demonstrations for the fix on You Tube! I love it when it is as simple as replacing a cap or two. I would have thought the same thing - that there may be something causing the caps to blow. But even if it isn't a matter of cheap materials but heat stress or some such thing that becomes an issue over time - at least you'll know what to do. Hopefully Acer has caught on and fixed the problem. It's funny - when I called Sony about the defect occurring with my video camera, they said they had no prior knowledge of that type of failure - yet a simple search on the internet indicated at least fifty or so other folks experiencing the same issue!
Your right, Nancy. The internet used to be my last resort for troubleshooting - now it's my first resort. You can't imagine the time it saves. Like they say - no sin is strange to man. If you have the problem, someone else already did, too.
Good point, Nancy. Today too many "prestige" manufacturers are no longer taking care of their good name: take for example Panasonic. It was considered that the very best TV screens available were the famous "Viera" plasma displays by that company. But, inexplicably, they decided to design their circuitry to intentionally diminish the contrast in several steps, so that the marvelous deep blacks and amazing contrast just went down the drain at "X" hours of use thanks to the on-purpose firmware. This intentional, "By design" move was probably made in order to make the panels last a given number of hours, but the buyer was actually cheated! As in your case with your Sony camera, the Panasonic plasmas were pretended to be free from defects, and operating "as designed"... but the owners kept noticing that the rich, deep blacks were turning a dull dark grey instead. I guess the Class Action Suite is still in the court, and the company still denies anything wrong, and keeps sending defective-by-design products to many unsuspecting customers. On the theme of counterfeit electronic components, I can attest to the seriousness of the problem: I've seen examples of almost perfect falsifications of large electrolytic capacitors dressed like Hitachi ones, but the initial performance is marginal and with many units open-circuited on delivery. the only way to identify these fakes is by checking the numbers in the official Hitachi catalog, where you can see the "FA" series does not exist in the Hitachi line of capacitors.
But the problem is much more serious when you start finding other components like TO-3 cased power transistors: I've seen and tested several examples of faked Motorola MJ15001 and 15002 power transistors that were in reality repackaged 2N3055 or similar!!! The fake factory got or implemented a way to imitate the exact appearance of the expensive, heavy duty 15001 by placing inside the can a much lesser, garden variety 2N3055. At first sight, the transistor looks and tests "good", but will fail miserably at higher currents or breakdown voltage, well under the authentic one specifications. The same is happening in IC's and many kinds of electronic components, so beware!. Amclaussen.
Does it really make sense that there are counterfeit electrolytics in the field? Seems to me that the bulk cost of such small parts isn't worth the effort to get them into mainstream distribution. Sort of akin to counterfeiting $1 bills. You need quite a bucket full to make a dent. But, $20 bills ..... now that's a different story!
I can see disreputable types counterfeiting processor chips, since the margins are greater.
In the words a a famous "philosopher / songstress", 'And the beat goes on ......'
Poor quality parts are always around, and nobody would ever copy them because they often have a bad reputation. But of course they are cheaper to buy than the good parts. two year capacitors are fine for products that will break in a year but be obsolete in six months, so there is a place for them.
At one time, long ago when I was servicing Sony brand audio cassette equipment, the bad caps mostly were Rubycon branded. They either opened up or developed excessive leakage, neither was good in audio equpment. So I learned quite quickly to replace certain value Rubycon caps because they were usually guilty.
Manyyears later one of the major semiconductor makers who was diversified also made IC sockets that often were intermittant. But they were cheap. So every time I wrote a purchase request for IC sockets I had to add the note: "## sockets are not acceptable". That company still makes a lot of good chips, but I don't think that they make sockets any more. Sorry about the name hint, but the guilty know who they are.
A Google search for images of "blown capacitor" retrieves hundredes of photos. One of my favorites was an image of a smll capacitor mounted in a larget capacitor body. Yikes. Wish I could relocate it.
Some name-brand companies license their brand name to second-class manufacturers, so having a brand name you recognize doesn't mean the brand owner actually manufactured the product.
When lab glassware carried the Pyrex trademark, I knew I could heat the heck out of it and it wouldn't shatter. But apparently some "Pyrex" branded cookware doesn't use real Pyrex-grade borosilicate glass and will crack or shatter. Don't try to heat water in Pyrex kitchenware on a stove burner! It just isn't the same as lab glassware.
Its interesting to see the comments this post has generated. Just imagine the number of TV's, Radio's and monitors (or any electronic equipment for that matter) that must be sold just because of a few poor-quality parts!! It just makes me wonder whether the companies that indulge in using poor components do so for saving costs (which would just be a few cents) or selling the next product (a new $200 monitor anyone!!).
I have known companies (not necessarily in the field of electronics) that use reliability engineering to engineer components to fail just outside their warranty period. In fact my old Japanese car had more than its fair share of part failures once it reached the six-year mark.
It begs me to question whether we, as good engineers, should succumb to the shackles of capitalism that drive bad practices? And if not, what could we do about it?
Sadly, I think in this day and age, consumers have gotten used to buying cheap stuff that they complain about which they have to replace later. It's more "fun" to relate a story on your facebook page of how your $10 toaster nearly burned down your house than it is to brag about how satisfied you are with your $50 toaster that works perfectly everytime and which you've had it for 10 years. If we valued quality engineered products, we'd consume less, spend less over the long term and have a higher quality of life.
Good points, Scott. I have a Sunbeam toaster that has lasted forever. Same with my TV, my blender, my coffee grinder, dishwasher, and on and on. What I see happening, though, is that consumers replace their products before they break, TVs especially. New features seem to be driving replacement at a rate higher than product breakdowns.
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