Capacitor Quality - Page 1
Forum section: electronics / projects

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 12, 2015, 11:24:45 pm
content: MOD:This thread was separated from the Siglent SDS3055 teardown:https://www.eevblog.com/forum/blog/eevblog-829-siglent-sdm3055-bench-multimeter-teardown/msg820233/#msg820233I wonder how much difference there really is between the lower-cost parts from "established brands" and lesser known (Outside China) brands like Lelon, Capxon etc.Designing something in just because they're an established name isn't necessarily good engineering when cost is a major factor.Given a fixed budget, what might they have skimped on elsewhere because they decided to use a more expensive part because of the brand name without really knowing if it's actually any better?IME of 30-odd years of repairing things, the biggest differentiator of capacitor reliability is heat exposure rather than capacitor brand.For caps that are not thermally or electrically stressed, I'd be surprised if there was much difference between brands.A "torture" test comparing performance of various cap brands might make an interesting episode...

author: c4757p
author_rank: Super Contributor
timestamp: December 13, 2015, 12:41:27 am
content: He won't... too afraid a non-Japanese capacitor might do well....

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 01:43:07 am
content: Quote from: mikeselectricstuff on December 12, 2015, 11:24:45 pmNo, but in this case there was evidence that they haven't skimped on every last cent for everything.And we have seen Nippon-Chemicon caps in a really horribly cheap PSU teardown before.QuoteAbout the "knowing" aspect. What engineer is going to do the hundreds or thousands of hours thermal testing required to test if some cheapie brand is up to scratch?You don't of course. If you deem capacitor life to be a potentially important factor in your product, then as a design engineer you do not take chances (budget allowing), you design in the top brand parts that have many decades of quality brand reputation in the industry. Do you think the tops brand have not earned their industry reputation?This is standard design practice that extends to many different parts and their specs on their datasheets, not just caps.For instance, you need a reliable reed relay. Do you trust a one-hung-low brand who's datasheet says 1,000,000 operations, or do you trust a Pickering with the same 1,000,000 rating? The answer is obvious. Therefore in reviewing or tearing down gear, it's important to look at this stuff.Same goes for using a genuine Analog Devices True RMS converter chip, or some asian knockoff as another example.A company can of course do extensive testing to qualify a lesser brand part, no problem with that, but that's an issue up to them. And unless they publish their results, the industry does not have anything to go on except the slow build up of experience over decades.QuoteI'm almost certain that you are wrong.The "bad capacitor" problem was a real issue in the industry:https://en.wikipedia.org/wiki/Capacitor_plagueThe major brands were not affected.And who discovered the problem? And ex-scientists form Rubycon.http://www.molalla.net/members/leeper/alumin~1.pdfBut sure, temperature and electrical stressing is always the major factor in capacitor failure.QuoteThe number of hours involved in doing that would be huge. And the likelihood of getting a null result would likely be high. As this issue is more to do with industry experience on a mass scale than one that can be easily reproduced.Image if I tested them and there was no difference? Would that prove that the crap brands are just as good? No it wouldn't, because collective industry experience proves otherwise.In this case it's much easier to prove a positive result (failure) than a negative one (no real failure/difference)But I agree that it would be interesting.

author: madires
author_rank: Super Contributor
timestamp: December 13, 2015, 01:47:06 am
content: Quote from: mikeselectricstuff on December 12, 2015, 11:24:45 pmOf course, heat exposure is the most stressing point in a electrolytic cap's life. But there are differences between brands. In some 20-25 years old audio stuff I've found a few bad low stressed Philips caps while beefy power supply filter caps from ROE (Rödermark, now part of Vishay) are still in specs.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 01:52:15 am
content: Quote from: c4757p on December 13, 2015, 12:41:27 amBut that's actually a real possibility.Then how do you explain a result that shows no major difference?Was the testing statistically significant at all? (likely not)Does it say anything about long term quality control of that manufacturer? (the answer is obviously no)I would hate if that happened and then everyone falsely used my video as some justification that the entire industry is wrong, and there really is no difference in production quality control of capacitors.

author: tautech
author_rank: Super Contributor
timestamp: December 13, 2015, 02:09:19 am
content: Quote from: EEVblog on December 13, 2015, 01:52:15 amSo you rate every leading manufacturer to stay at the top of their game.And none of the others to evolve and challenge them.History has proven every dog has their day.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2015, 02:20:06 am
content: Quote from: EEVblog on December 13, 2015, 01:43:07 amWell at last that's what the label says - these days it's hard to know if parts used in really cheap gear are genuine or not. A label on a plastic sleeve is pretty low down the scale of difficulty for faking,QuoteI'm just questioning the assumption that all lesser known brands are necessarily inferior, or even have that production in recent years has a better track record. As consumers/reviewers we only see an infinitely small sample and neither of us have worked in the real industry recently enough to have experience of what is coming out of any capacitor factory nowadays.The established names are having to compete at the lower end, and there's only so much that their customers will pay for the name, so their production methods for their cheaper parts aren't going to be too different from anyone else, though you might hope (with no way of actually knowing) that QC may be better.A quick search on Digikey for 100uf 16V 105 deg radial caps shows parts from all the major established brands below GBP0.04 at 10K. I don't think it's reasonable to expect these to perform as well as the ones you find still going string in a 30 year old piece of testgear.A company like Siglent may well have been using a particular Obscure (to us) brand by the hundred thousand ( and possibly their subcontractors, millions) for long enough to have at least as much confidence in it than any of the ones we know from Digikey, maybe more.All I'm saying is that maybe there's a little too much emphasis on choice of cap brand as an indicator of quality, based on minimal actual evidence. NCC/ELNA/Panasonic etc. = good ( at least in intention, probably). Unknowns = maybe no better or worse, we don't know.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2015, 02:23:28 am
content: Quote from: EEVblog on December 13, 2015, 01:43:07 amYes but it's something that could be just set up and left to get on with itself over a few months with minimal actual attention. Though possibly not in an office environment - you wouldn't one of those expensive fire-service callouts because a neighbour smelled a smouldering capacitor...

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 02:26:42 am
content: Quote from: tautech on December 13, 2015, 02:09:19 amOf course not, but it's not a bad bet.QuoteOf course they can, and I encourage that.How abouttheyactually do the testing, or pay someone like UL to do independent testing to prove how good their capacitors are?But of course this will end up as "Dave doesn't want to do the testing because he's afraid blah blah".Why does it have to be about me?How about you go do the testing and publish some results? How about Mike?Go to the Lelon website for example. Where are the white paper on quality control etc?Just some crap on their ISO quality control:http://www.lelon.com.tw/en/about2.phpWhat are they doing to prove to the industry they are any good and can be trusted for long term quality control? Which they have even more incentive to do being one of the major player in the "bad cap" problem over a decade ago?

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2015, 02:31:47 am
content: Quote from: EEVblog on December 13, 2015, 02:26:42 amIt could be argued that someone who has had a problem and fixed it is a better bet than someone who has never had a problem, as they've learned from their mistakes, while the others may have just been lucky."That employee's mistake just cost $50,000, aren't you going to fire him?"Boss : "Why would I do that? I just spent $50,000 training him..."

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 02:34:48 am
content: Quote from: mikeselectricstuff on December 13, 2015, 02:20:06 amSure, nothing wrong with, and I support that.Doesn't change the fact that the big brands have the rep and the small ones don't.It's not just me on some capacitor fanboy crusade, people keep asking for and talking about what brand caps are used in products, so I always point it out as a matter of course.QuoteYep, and you can work in the industry for 40 years and still have very little real quantifiable experience in capacitor quality and reliability, apart from the anecdotal .QuoteOf course, it's a brand trust thing.QuoteThey may well have.QuoteSure. But once again, there are top names in the business, and they have built that rep over decades. For me as an experienced design engineer not to share that info with viewers would be bad form.If someone asked me (and they do, a lot) what brand capacitors are deemed to be the best quality, then there is a very real list for that, whether anyone likes it or not. or whether it's fair or not.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2015, 02:47:42 am
content: QuoteNot that they do very often, but if someone asked me I'd suggest that they are asking the wrong question. Like when someone asks what's the best microcontrollerYou basically get what you pay for, and that the way that caps are used, in particular heat exposure and ripple current, is probably a more significant factor than differences between brands at a particular price point.A badly laid out PSU full of NCCs running very hot is probably going to die before a well-cooled one full of CapXons.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: December 13, 2015, 02:54:28 am
content: Quote from: EEVblog on December 13, 2015, 02:26:42 amLots of even fairly high-end Chinese companies have crappy websites. I don't think you can read anything useful into that. they clearly don't need marketing wank to sell their product - they're too busy making stuff to mess about with corporate fluff like White papers etc. It's a totally different culture.The big brands do all that stuff as marketing to maintain their image to justify their price premium, and to satisfy their higher end customers, who the Chinese don't care about selling to as the volumes are too low.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 13, 2015, 03:08:44 am
content: Quote from: EEVblog on December 13, 2015, 01:43:07 amWell... a good engineer, of course.Typical example: product that's been in production for a year. Time for a round of cost-reduction.That's one round of parts out in the field. Accelerated life tests can be done to qualify new (potentially cheaper) substitutes. Once a choice is made, another round of production can be sold, and evaluated by the marketplace as a whole (hopefully, without requiring recalls).This is not something that will normally apply to < 10k/yr products, or to new design (unless you've personally done all that qualification yourself, or someone has that data available), which is likely the range of experience of most designers here.But to categorically disregard such a step out of hand, is bad engineering!Tim

author: rsjsouza
author_rank: Super Contributor
timestamp: December 13, 2015, 03:33:30 am
content: Quote from: EEVblog on December 13, 2015, 01:43:07 amIt is somewhat ironic when you link this thread with the last sentence of the PDF article above:Teapo suspects it is an attempt by Japanese aluminum capacitor suppliers to gain market share, and that the unfortunate incident involving a few companies willunfairly categorizethe entire aluminum capacitor industry in Taiwan.Coincidentally, your immediate suspicion of Jamicon branded caps in episode #824 (14:30) reflects that same fear. Still from the same article:Further intelligence revealed that Kamei/Jamicon sources its electrolytes from Sanyo in Japan, and likely was not affected by the faulty electrolyte supply.All that said, in my opinion it is caveat emptor. Some top brands have their track record (despite some goof ups happened in the past with a few of them) while others are the "Rigols/Siglents" of the cap world with their hits and misses. In both cases you always have to look at Mike's post: unless you are a very high volume customer that could potentially request additional test information, you get what you pay for.

author: tautech
author_rank: Super Contributor
timestamp: December 13, 2015, 03:37:21 am
content: It should be made mention that this thread (probably wisely) was ripped by Dave from the Siglent SDS3055 teardown:https://www.eevblog.com/forum/blog/eevblog-829-siglent-sdm3055-bench-multimeter-teardown/msg820233/#msg820233Just to put the opening discussion in context.....BTWMike, you have another thread to your name now.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 03:48:15 am
content: Quote from: mikeselectricstuff on December 13, 2015, 02:47:42 amNo doubt.But that's actually a different question to which have the best reputation for quality.

author: calexanian
author_rank: Super Contributor
timestamp: December 13, 2015, 03:49:32 am
content: What really is more important in cost saving in components, and particularly in caps is knowing the supply chain. If even a lesser brand can be just fine so long as they meet their own specs, but a high quality brand can suffer if an unscrupulous vendor or broker sells you old, damaged, or fake parts. Knowing the supply chain can really make or break your product.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 03:50:28 am
content: Quote from: T3sl4co1l on December 13, 2015, 03:08:44 amI of course didn't mean to imply that.But obviously no practising engineer has the time and resources to do that sort of testing for regular product design.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 03:55:25 am
content: Quote from: mikeselectricstuff on December 13, 2015, 02:54:28 amYep, that's the real world whether you like it or not.No one can complain that a component maker "unfairly" doesn't get a good rep for quality if they don't actively show it and explain it and provide evidence (worthwhile of not). The only other way to build up a quality rep is over time by having your product used for decades without any major issues.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 04:09:30 am
content: Quote from: T3sl4co1l on December 13, 2015, 03:08:44 amAnd that's the trick, it'smoreof risk going with a lesser known brand.I've done stuff like this. But in the case of capacitors that are fairly complex chemically and rely on good and consistent manufacturing quality, my report to Management after said testing is going to say something like this:"Accelerated life testing was performed on N products of X brand, under Y conditions, and indications are that they may be as reliable as brand Z. But this testing is only representative of small sample over a small batch time period, and may not reflect the long term quality reliability of company X. There will still be some risk with going with company X long term until long term field testing data is in."Or something like that.Basically, any professional engineer knows there is some risk with going with that new brand based on some accelerated life cycle testing on a small sample.A lot of engineering is about lowering the risk and using "best practice". It's like the old "Nobody ever got fired for buying IBM/Fluke/Keysight etc".In the case of caps, no engineer ever got fired for designing in Panasonic caps if it's within the budget. It's smart design.If for some reason those Panasonic caps went tits-up because they had a production problem, then no one is going to hound you for the choice of using those Panasonic caps. If you used CapXon, well, good luck defending that choice.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 04:18:37 am
content: Quote from: blueskull on December 13, 2015, 04:14:12 amNo one will argue that.

author: BravoV
author_rank: Super Contributor
timestamp: December 13, 2015, 04:40:29 am
content: Even using a branded 1st tier cap, apart from external heat exposure, still curious if a crappy design job can be a factor say like the circuit works constantly exceeding the cap's rated max ripple current ?Wondering if there is such dedicated circuit just to torture a cap on it's ripple current ? Like an AC/pulsing adjustable current source to heat up the cap internally.

author: SeanB
author_rank: Super Contributor
timestamp: December 13, 2015, 07:36:59 am
content: Simple way to stress test a capacitor is to put it in a small plastic box, chuck in the nastiest SMPS and power it 24/7. Also known as a knockoff phone charger, most have a low brand or non name brand pair of capacitors inside, which will die in a year.I just took a Multichoice PVR apart here, mostly because I do not watch TV, and because i wanted the 500G WD drive inside. PSU is all Rubycon KY series and the main boards are a mix of Rubycon and Nichicon, though there are a fair number of Teapo as well, and 2 small 10mm diameter 10mm high 100uF 16V pale blue no name 85C capacitors there as well. 2 gold Lelon caps there as well on the main ASIC board by the power input. The main reason these fail is because they are placed nicely in a warm TV cabinet, with no airflow, and, even though they do have a little Sunon fan to move the air inside over the hard drive, they cook. Other failure is the tuner modules cook themselves, or they get killed by lightning.

author: tautech
author_rank: Super Contributor
timestamp: December 13, 2015, 07:41:03 am
content: Quote from: rsjsouza on December 13, 2015, 03:33:30 amThis^And from the Wikipedia article:QuoteAnd:QuoteYet to be discussed is HOW cap ratings are applied in designs today.It is my strong opinion that most componentry is used in excess of safe real world values. In that I mean not using a part, any part, at close to any of it's maximum ratings.We commonly see failure of all sorts of components in all sorts of equipment, many for just a few cents more would have been avoided with a better rated component.Where do caps fall in this; it is my opinion that they should be given more working tolerance below their maximum ratings, look at designs of yesteryear where it was common to see additional capacitance and voltage headroom used. Not any longer.Obviously the reason is cost, the point being IF so called 2nd rate caps were used conservatively (and ALL should), would we have the concerns over cap brands that we do today?So where do you set the maximum value of any specification for capacitors in new designs as a proportion of Datasheet maximums?65%, 75%, 85%, 95% ?Will it have a bearing on expected life? You bet you it will.Quote from: blueskull on December 13, 2015, 04:46:30 amFixed that for you.

author: funkyant
author_rank: Unknown
timestamp: December 13, 2015, 09:11:36 am
content: A lot of you probably are aware that there's a whole forum dedicated to the pursuit of identifying crappy caps to avoid. Tales of Electrolyte recipe espionage and everything (ha!):http://www.badcaps.net/index.php?pageid=about_us

author: jitter
author_rank: Frequent Contributor
timestamp: December 13, 2015, 09:12:53 am
content: I wonder how this discussion of A-brand vs B-brand caps is different from audiophile vs standard caps.Sure rubbish C-brand caps in a hot environment fail quickly. I have torn down several failed power supplies (plugpacks and built in) which had C-brand caps in them. But they also were cramped designs running way too hot for long life. But I have yet to come across failed B-brand caps. Even my PC PSU bought during the capacitor plague era and filled with the now dreaded Teapo caps still functions OK, and it has seen quite some hours of service.In my work in industrial electronics I mostly come across A-brand caps, no doubt.But what are A-brand caps? For some reason, the ones mentioned all the time are Nichicon, Nippon Chemicon, Panasonic and Rubycon. But over here, you'll also come across Vishay/BC (formerly Philips) a lot and are considered A-brands. Would that brand be considered an A-brand in your part of the world?

author: funkyant
author_rank: Unknown
timestamp: December 13, 2015, 09:21:18 am
content: In the end, the best people to ask about caps are not design engineers - it's the repair techs.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 09:22:06 am
content: Quote from: wilfred on December 13, 2015, 08:11:46 amProfessional design engineering isallabout tradeoff's. In fact it's almost part of the definition of practical engineering.No engineer has infinite time and money to optimise every single component in the design, and test/characterise/lifecyle test every component in the design.So what do you usually do for good design practice? Design specs aside, you chose the best quality parts you possibly can based on industry experience and brand reputation, that is possible within your budget.In fact part of good experienced designer is knowing about brand reputation etc and applying that accordingly.If you aren't doing that, and are just blindly following datasheets specs as if all manufactures and their parts are all created equal and have potentially equal quality , then I'd say that you aren't a very knowledgeable design engineer.Indeed, if you sat in a design review meeting for a design where reliability was paramount, and tried to argue that you should use CapXon caps instead of Panasonic, then after being met with snickering and looks of incredulity, you'd get a very stern "prove it".No that may not be "fair", it may not even be "right", and the no-name caps might perform just as well as the name brand ones, but would you stake your professional reputation on it?If a no-name cap company wan't to earn their place in "the list" of proven quality cap manufacturers, then it's up to them to do that.Welcome to the real world.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 09:48:48 am
content: I sense a new movement happening - Capacitor Justice Warriors (CJW's)They could be a new plague (pun intended).I suggest they join forces with the Uni-T Justice Warriors (UTJW's). Strength in numbers

author: iampoor
author_rank: Frequent Contributor
timestamp: December 13, 2015, 09:53:40 am
content: Interesting how the supply uses Analog Devices parts, delta fans, Omron Relays, A Caddock precision divider, and then......5 lelon caps?!? Doesnt seem to me like they were really trying to save any money....besides those caps and steel chassis. (Im 10 minutes into the video). Im not sure if that means those caps have been properly speced, or they just have a nutso purchasing manager. God questin for Eric next time.

author: wraper
author_rank: Unknown
timestamp: December 13, 2015, 09:55:54 am
content: Quote from: blueskull on December 13, 2015, 04:14:12 amBS, if they are both operated in not very hot environment, NCC cap most likely will outlive that Crapxon with a huge margin. Some series of crapxons bulge even when just sitting on the shelve. Temperature rating should be taken with a grain of salt, it not indicative of quality at all.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 10:02:32 am
content: Quote from: iampoor on December 13, 2015, 09:53:40 amIt's likely that the designer did not specify a brand. The BOM could simply have "1000uF 10V RB 5mm pitch Electrolytic".And/or Siglent get a good deal on Lelon caps and simply uses them in a ton of products.Indeed, the BOM could actually specify a specific Lelon part number, and the designer simply picked that part from the company approved schematic parts list.Whether or not someone at Siglent actually sat down and thought about and/or tested or investigated Lelon, and/or approved them and/or made any sort of cost/quality tradeoff is possibly, but I suspect more unlikely than not.Maybe there is some really pissed off engineer at Siglent who's a Panasonic fanboy and speced those in, only to be usurped by the purchasing department and the powers-that-be.Can be a whole host of reasons and scenarios.

author: Zero999
author_rank: Super Contributor
timestamp: December 13, 2015, 10:08:45 am
content: LOL once I was desperate for a capacitor to use a in a prototype, so I pulled an old Crapston capacitor from an old monitor, tested it and it still read the full capacitance so I used it and it worked fine. Of course if it was for production, then I'd use a decent brand capacitor. I don't see the point on saving a few pence on a capacitor, only for it to go wrong and cost a lot more in future.Despite their bad reputation here, some of the most reliable capacitors I've seen are solid resin dipped tantalum. At work we have plenty of them on PSU boards which are over 30 years old and have been running nearly 24/7 for all their life, without a single failure.

author: iampoor
author_rank: Frequent Contributor
timestamp: December 13, 2015, 10:13:40 am
content: Quote from: EEVblog on December 13, 2015, 10:02:32 amVery true. Just seems like every other part on the board with a brand name is a reputable vendor! Even the fuse holder looks great! It will remain a mystery.

author: SeanB
author_rank: Super Contributor
timestamp: December 13, 2015, 10:17:19 am
content: Quote from: EEVblog on December 13, 2015, 10:02:32 amI would guess they have a list of preferred parts, so use them in design. Could be that they got them in bulk for a good price, and find them reliable enough, or they have had good previous experience of them, or they just had a load left over from a previous production run and are rolling them out as fit for purpose here.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 10:23:33 am
content: So how would one go about accelerated testing caps like this?Off the top of my head I'd say:- Chose at least two name brand, and two crap brands.- Same temp range, rated hours @ similar ESR, size, etc.- At least 5 samples of each type.- Only buy from authorized distributors to avoid fakes (maybe not possible for the crap brands)- Buy each one from 5 different suppliers (Digikey, Mouser, Farnall, RS etc) to hopefully avoid and batch related quality issues.- Test the ESR and other parameters of each cap before testing. Might as well test everything I guess, cap, leakage etc- Put them all on the same board with individual and identical bridge rectifiers and loads. No parallels!- Pick a ripple current to stress the parts somewhat. Normally speced at 100KHz, but testing with normal 100Hz full wave should be fine. Although if you wanted to get fancy pantsy, 100KHz SMPS for each one.- Pick a voltage close to the max working voltage- Put in thermal chamber at say 85C- Run for 1000 hours.- Test all parameter of every cap every 100 hours, after letting settle to room temp.- Also try and see any difference in internal heating with FLIR.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 10:35:11 am
content: Quote from: Hero999 on December 13, 2015, 10:08:45 amAnd therein lies the dilemma of every design engineer, and probably a good part of the reason why certain brands are "respected", and passed down as such through the generations. Engineers like having known go-to parts/brands, it's part of our nature.Of course the CJW's will insist that every capacitor/part should be judged on it's merits etc. And yeah, ok, fine, but try and justify to the engineering manager why you want to spend 100's hours testing CapXon caps, when it's well accepted that Panasonic is a respected, safer and easier choice.An almost identical argument would be for lithium-ion batteries. Like capacitors, it's all about the quality control and design of chemicals and other manufacturing processes.Panasonic is a no-brainer decision for a quality reputation in batteries. All other things being equal, and cost aside, a design engineer and the "higher-up's" would all be just fine with picking Panasonic batteries without further justification. Suggest WunHunLow and you might have a fight on your hands to get them approved.

author: VK5RC
author_rank: Unknown
timestamp: December 13, 2015, 10:42:39 am
content: Isn't the problem the lack of independently verified data about component MTTF. To do it properly is seriously hard, lots of samples, over different production runs, different models, temps, sizes etc. I suspect the firms have the data but keep it very close to their chest, like car warranty claim costs.So much of what you hear is hearsay, if I have an important project I spend a little more though!

author: SeanB
author_rank: Super Contributor
timestamp: December 13, 2015, 10:47:07 am
content: Might also want to build a 100kHz power oscillator ( capable of around 5A of current) and put them all in series across the output, and keep them all at the same constant AC current and run at 90C for 85C units, or 120C for 105C units. That way you have the most dissipation in internal ESR, and the higher temperature will provide reduced test time, plus will still be usable as a typical in case temperature. Just chose those with similar max ripple current and run in a string of mixed types. As ESR will be low you probably could get away with a 12V supply rail as power source, enabling you to use COTS parts for the output stage, along with using a single supply.

author: Muttley Snickers
author_rank: Unknown
timestamp: December 13, 2015, 10:48:13 am
content: The particular meter mentioned is supplied with a three year warranty so I would assume from this that the manufacturer has designed for and expects the incorporated componentry to be trouble free for at least that period, notwithstanding components could still fail or go out of tolerance within that period and cause erroneous results which may not be immediately recognised by the user until some strange event occurs.I dont know whether a device that is out of original specification is fully covered under a warranty agreement, but if the device was so far out of whack after a couple of years then I would hope that most manufacturers would come to the party and provide a repair but this may not be the case in all circumstances.

author: firewalker
author_rank: Super Contributor
timestamp: December 13, 2015, 10:51:31 am
content: Quote from: EEVblog on December 13, 2015, 10:23:33 amThere should be on-off session. E.g. once per day. Cut the power, allow everything to cool and restart. To simulate turn on-off events. Daily thermal expansion and contraction could play a role to the life of the component.Alexander.

author: iampoor
author_rank: Frequent Contributor
timestamp: December 13, 2015, 10:52:31 am
content: Quote from: EEVblog on December 13, 2015, 10:23:33 amGetting a few fakes would be interesting too.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 11:55:48 am
content: Quote from: wilfred on December 13, 2015, 11:05:01 amNo, and I'm not going to try and explain why again.QuoteAs a professional design engineer for 20+ years I covered my arse with monotonous regularity. Anyone who doesn't is a fool who'll get taken advantage of.QuoteOf course it's a part of it, and a very legitimate part of it. In many cases an actual legal requirement and regular part of professional practice.Doesn't mean there is no quantitative justification for it though.That's the end for me, I'm done discussing this aspect of it.

author: EEVblog
author_rank: Unknown
timestamp: December 13, 2015, 11:57:00 am
content: Quote from: firewalker on December 13, 2015, 10:51:31 amCan't hurt.Or maybe it can, and that's the point

author: diyaudio
author_rank: Frequent Contributor
timestamp: December 13, 2015, 12:44:36 pm
content: WIMA makes good caps....

author: wraper
author_rank: Unknown
timestamp: December 13, 2015, 01:03:05 pm
content: Quote from: firewalker on December 13, 2015, 10:51:31 amExactly, but it's not sufficient anyway. Many crap capacitors performed accelerated tests just fine. But when they reached the real world, turned out they fail prematurely. For example Nippon Chemi-con KZG series or Nichicon HM, HN series if talking about good brands. I have read a while ago that high voltage and temperature used in accelerated tests prevented some negative effects which caused capacitors to fail in real use conditions.

author: retrolefty
author_rank: Super Contributor
timestamp: December 13, 2015, 01:28:12 pm
content: Quote from: funkyant on December 13, 2015, 09:21:18 amDing, ding, ding. We have a winner.Now if there was only a decent broad based database of caps by brand repair activity to guide us out of this problem with 'reputation Vs unknown brand problem'. So far there is a large subjective element stated so far by many.

author: Seekonk
author_rank: Super Contributor
timestamp: December 13, 2015, 02:44:21 pm
content: Our company had this legacy product. The product was the responsibility of engineer X.A customer that operated the product 24/7 on 50Hzsaid the product would fail after about 2 1/2 years.It wasn't that expensive and most customers would have just keep a half dozen on the shelf andplugged in a new one. He persisted trying to find out the problem. Engineer X thought he was a moron.When the product was tested at 60Hz it worked fineEngineer X went on vacation for two weeks and when the customer called again I was told to resolve theproblem. Testing it indeed showed a problem. The dropout time of the relay was shoryer than 50Hz. Thesupply cap was open and the shrink label was a totally different color than a new capacitor. This babywas hot! We used a good quality cap and looking at the operating temperature, these failures were happeningright on the money time wise. That was reassuring that the calculations actually worked.We had an ISO9000 quality system and I was a trained auditor. When I first started working there I had toget a product number assigned in order to get parts. We offered a lot of custom variants on standard boards.I would be working at my desk on the product when production would bring me a box of 25 units that didn'twork. They had managed to build these, test them, and make labels before I had even designed the unit.Production did not need an engineer to sign off before construction. With that happening four times I hadgotten a reputation of designing things that didn't work. After that I just stole parts from inventory.I tried to change the procedure but they fought me tooth and nail. Left three years later with nothingresolved.I was responsible for failure reports for products that were returned. There were no reports done onnew products off the line that didn't work. One day I was back in repair. There were 35 units with theboards taken out. There was a resistor in series with a pot. Test procedure said if it couldn't beadjusted, change it to this value. That was likely to happen on one of every 200 units. A transistorwas discontinued and changed to one similar. For ten years they had been pulling apart 50% of the unitscoming off the A resistor change reduced failures to about zero. line. Production refused to track newunits that failed.Management just wanted to buy a quality system, not live it. When Sales slump the owner would create a newmission statement. You need buy in from everyone. A worker at a capacitor plant is likely to throw hisold apple core from lunch into the vat of electrolyte.

author: nctnico
author_rank: Super Contributor
timestamp: December 13, 2015, 03:05:23 pm
content: Quote from: EEVblog on December 13, 2015, 01:43:07 amYou can buy crappy capacitors from reputable brands as well. You can actually buy 85 degrees capacitors with a longer service life then 105 degrees capacitors. Without digging deep into the capacitor's spec sheet there is no way to tell what has been designed in. You really need to look at the service life and temperature rating of a capacitor to make a meaningful comparison. And then again a designer can have opted to use a bigger or smaller capacitor.

author: tszaboo
author_rank: Super Contributor
timestamp: December 13, 2015, 03:17:21 pm
content: Quote from: EEVblog on December 13, 2015, 10:02:32 amWe both know this is a design practice to some, and agree it is a guide to failure.It doesnt even take a capacitor, it can be even semiconductor, write the manufacturer there. I had LM317s, which produced very different overshoot for different manufacturer. I had TVS diodes, same part numberwhere the TSMC (your video card likely to be produced there) had 10 times the leakage current than the ST part. I had Crystal oscillator, the same fracking farnell code, Multicompwith different drive capabilities from batch to batch. There are no compatibles, at least not in a precision equipment.Some years ago, a product of mine went into series production. The supply chain manager came, and told me that the subcontractor want to make it with Lelon, instead of the Nichicon, I've designed in, can I approve it? Never even heared about Lelon back then. They wanted to save something like 0,5% of the total cost with the different brand. If the board fails, some service engineer has to get on an airplaine, and travel to maybe japan to replace the board. I did not approve it, got my manager support for it. We made it with Nichicon, to date, never had a single one failed with this problem. There is a power supply next to it, made by Meanwell, it is using capxon and other brands. They did not fail either.The moral of the story: I did not had any sleepless nights, knowing, that I made the right choice. Because it is not just "probably" working.

author: amyk
author_rank: Super Contributor
timestamp: December 13, 2015, 04:51:32 pm
content: Quote from: funkyant on December 13, 2015, 09:21:18 amI don't think so, because everything they see is defective in some way. There's a huge selection bias there. The infamous capacitor plague aside, perhaps they see more bad Chinese caps than Japanese ones simply because far more equipment uses the former.About endurance testing, the BadCaps forum boss tried it a few years ago, but the results were... you can read for yourself:http://www.badcaps.net/forum/showthread.php?t=2179&page=10This also reminds me,1000hr@105C decoupling capright under a laptop's CPU.That was clearly planned obolescence...

author: calzap
author_rank: Frequent Contributor
timestamp: December 13, 2015, 05:27:24 pm
content: Quote from: amyk on December 13, 2015, 04:51:32 pmYou make a good point. In addition, even if cheaper brand caps are seen to have failed more often by repair techs, there can be other factors than them being more common. They may be used if more iffy designs with regard to cooling, voltage regulation, etc., and the support components and manufacturing practices may not be as good. In addition, customers may place cheaper end-products in harsher environments or treat them with less care.I'm not minimizing the role of repair techs in ferreting out bad quality and outright mistakes in design and manufacturing. They are invaluable in this role and are sentinels whose warnings have to be investigated.Probably, the only satisfactory way to compare brands of caps is competent testing by an unbiased lab. It would have to be an on-going process because today's winners could be tomorrow's losers. How to get it done though is the tough part.Mike in California

author: Fungus
author_rank: Super Contributor
timestamp: December 13, 2015, 05:27:38 pm
content: Quote from: mikeselectricstuff on December 13, 2015, 02:47:42 amThis.Capacitor choice is only a small part of the design.If you design it so the capacitors don't get hot then you don't necessarily need top brands.Of course such designs might need you to put caps in parallel to reduce ESR, etc., so you might end up paying the same. Even so, it could still be a more reliable design than just spending top dollar on fancy caps then stressing them.

author: station240
author_rank: Unknown
timestamp: December 13, 2015, 05:45:23 pm
content: I wonder how much of the capacitor quality issues are related to electrolyte, and how many are due to 2nd rate plate materials.From what I understand about Gel Cell batteries, the really high quality (10 year warranty) batteries use virgin lead, where as the ones that die after a few years use recycled lead (no doubt from previous cheap batteries). I wonder how much of a factor this sort of thing is in capacitors as well ?

author: dexters_lab
author_rank: Unknown
timestamp: December 13, 2015, 07:53:53 pm
content: Dave, one thing i have noticed taking caps apart is the quality of the aluminium foil, the cheaper brands seem to have visible defects on them, streaky lines on the anode (normally matt grey from the oxide layer and etching) and blotchy patterns on the cathode (normally brighter / silvery)The better brands seem to have a better quality finish so you might want to open a few of them up to compare, could Ben Krasnow help out using his SEM?Other things might affect the long term reliability, like the quantity and purity of the electrolyte and it's paper carrier. Could a cheaper brand skimp on the quantity of electrolyte so there is only just enough, a better brand might include a little more to help prevent drying out over time and have a better long term reliability? No idea how you might test for this though.have attached a great document from Nichicon about the finer technical details of electrolytic caps, well worth a read

author: madires
author_rank: Super Contributor
timestamp: December 13, 2015, 08:04:34 pm
content: Quote from: dexters_lab on December 13, 2015, 07:53:53 pmThe forming process is also important. Cheap brands could speed up the forming process to reduce costs, i.e. thinner oxide layer.

author: Zero999
author_rank: Super Contributor
timestamp: December 13, 2015, 08:46:46 pm
content: Quote from: amyk on December 13, 2015, 04:51:32 pmThat's not good but those capacitor seem to be be solid, not wet electrolyte so should be more tolerant of heat, than wet capacitors.

author: engiadina
author_rank: Contributor
timestamp: December 13, 2015, 10:27:50 pm
content: Regarding Leylon caps ...I did some consulting for a large company in terms of component procurement. They actually did long term tests and stress tests with various brands of capacitors.What I can say from that is that the tested Leylon caps were equal to Nichicon, Nippon Chem, Panasonic. I've been a bit biased as well. But I have to admit that those Leylon caps performed excellent.

author: plesa
author_rank: Frequent Contributor
timestamp: December 13, 2015, 10:49:47 pm
content: I think that all vendors have their own pandora's box. Some of them in this box have only batches, some of them product series and some of them their whole portfolio:)On product level soldering process (time and temperature) affect capacitors lifetime as well. So it is not only the manufacturer of components who can screw thins up.Many times I saw that designer did not consider all design aspects and voltage rating were underrated.

author: EEVblog
author_rank: Unknown
timestamp: December 14, 2015, 12:04:21 am
content: Quote from: dexters_lab on December 13, 2015, 07:53:53 pmThe problem there is you really have to know the electro-chemistry involved in capacitors to know what's good/bad or what actually makes a difference.

author: Fungus
author_rank: Super Contributor
timestamp: December 14, 2015, 12:59:28 am
content: Quote from: retrolefty on December 13, 2015, 01:28:12 pmNot necessarily. Some product brands/engineers will stress caps more than others.Will somebody who's rubbish at cooling but always chooses good capsnecessarilywin out over somebody who always buys mid-range caps but knows about cooling, owns a thermal camera and often puts two (or more) caps in parallel where there's high stress?

author: Tothwolf
author_rank: Regular Contributor
timestamp: December 14, 2015, 06:48:40 am
content: Quote from: wraper on December 13, 2015, 01:03:05 pmNippon / United Chemi-con KZG and KZJ series parts were defective in design and have a 100% failure rate.The ultra-low ESR Nichicon HM and HN series were decent parts. According to Nichicon, they had at least one production line which was overfilling the electrolyte in these two series. HM and HN series parts made after 2004 are perfectly fine (I continue to use NOS late production HM and HN parts as replacements for faulty Nippon / UCC KZG). The HZ series (HM->HN->HZ) seems to not have been affected at all.Some people have confused the faulty Nippon / United Chemi-con KZG / KZJ and the batch of defective Nichicon HM / HN parts with the earlier "capacitor plague", however all three of these are distinct events.

author: fanOfeeDIY
author_rank: Unknown
timestamp: January 01, 2016, 02:25:41 pm
content: Hi,I used to work for a Japanese Manufacturing Company and would like to share about my experience.The biggest issues for selecting the good quality electrolytic capacitor are that:(1)No *economically* good method to evaluate or test the reliability and durability of capacitors when the capacitors arrived at the factory and before assembling to the product.(2)There are so many fake or counterfeit capacitors get *mixed* even going through the company’s procurement department or using named distributors.For the above (1), measuring capacitance, ESR and leakage or some companies have more know-how to test them, but bad caps are really difficult to reject them before putting into assembling lines. Even using the cheap or no brand name’s capacitors will pass the QA test of the final stage of assembly lines.After the products sold in the market, the bad cap fails after about two or more years later which is no good way to *predict*.As a result, the discussion of selecting the good quality capacitors do not become technical talk, it becomes more like a trust, hunch and experience of the past.This is one of the reasons, so many companies relay on the brand of the capacitors.Because having the leaking electrolytic capacitors are one of the frequent faulty claims of the product from the customer, which could lead ruin the Manufacture’s reputation.It is deadly serious situation.As a result, the electrolytic capacitor is similar to The Market for Lemons, and this is the reason well-known companies, who would like to have good reputation, have tendency to select the capacitor by the brand of the capacitor.BTW, nichicon and nippon chemi-con are completely different companies.

author: fanOfeeDIY
author_rank: Unknown
timestamp: January 01, 2016, 02:49:50 pm
content: If you going to select the electrolytic capacitor by the brand name, this is a chart posted on a forum in Japan.Listed from known to be good quality from high on top to low.(1)nippon chemi-con, Sanyo (acquired by Panasonic), Hitachi(2)nichicon , Panasonic, Rubycon------- Above is top category ------(3)ELNA(4)TEAPO-------Above is normally good, from here is one of the wall of reliability -------(5)CapXON-------From here, it is not recommended in high load circuit -------(6)OST------- From here, would be better to avoid if it is possible to avoid-------(7)Jackcon, Fuhjyyu------- From here, known to be high percentage of failing-------(8)G-Luxon, Lelon------- Others, avoid them.......-------But this information is nothing back uped with techinical reason.It is more like a preference.

author: wraper
author_rank: Unknown
timestamp: January 01, 2016, 03:04:32 pm
content: Quote from: fanOfeeDIY on January 01, 2016, 02:49:50 pmThis chart is really stupid. Putting Elna and teapo together, Crapxon over OST, Fuhjyyu (cheapest crap you can get) above G-luxon and lelon (not so bad capacitors actually)QuoteThis chart is missing most of more or less decent mid range caps which are better than teapo. And BTW Teapo and G-Luxon (2nd and bottom grade in your chart) are the same company and owned by Yageo which sells caps under their own brand too. Check the main page of the websitehttp://www.luxon.com.tw/

author: wraper
author_rank: Unknown
timestamp: January 01, 2016, 03:52:52 pm
content: Quote from: blueskull on January 01, 2016, 03:31:47 pmThere is no Sanyo for many years. Either you go for Panasonic (OS-CON) or Suncon (which became independent company) for liquid.QuoteJust LOL, considering they are not made for many years.

author: ciccio
author_rank: Frequent Contributor
timestamp: January 01, 2016, 06:14:58 pm
content: I'v read this thread only today.I've a not big experience in capacitors used in switching PSU, except for some motherboard repair, but I have a lot of experience and reliability data (experimental) on electrolytics used in standard PSU and dc filtering on board.I read that Lelon has a bad reputation. My experience is the following:About 35 years ago we got maybe the first lot of Lelon caps sold in Italy.I remember well those 1uF, 50 V caps, used to control the time constants in a compander circuit: we had to replace more than 50% at test time, because they were open circuit or very (+1000 %) out of range.So we put Lelon on our "black list".After one year our suppliers were all out of stock for 22uF 35V caps.The only available were Lelon, so the boss said OK to them, but check wery well.They worked flawless (and sure they were, because we had zero returns imputable to them, and we were buying tens of thousands of them).In another case, about 30 years ago, I assembled the prototype of a new graphic equalizer board, did not check well the artwork and two of these Lelon caps were installed with reverse polarity, on +/- 15 V supply lines.Well, we discovered my mistake after about 500 boards / 2 years, when Lelon was replaced with another brand, which went into flames / magic smoke at first switch-on. We contacted some of our customers and checked some old boards: capacitors were reverse biased, but still into specs. Obviously we replaced them, with the correct polarity.Shure, all what I wrote above has no real meaning, because electrolytics are not supposed to work with reverse voltage applied, but it makes me believe that Lelon is a reliable brand.

author: Wester547
author_rank: Newbie
timestamp: February 11, 2016, 11:15:32 pm
content: Quote from: Tothwolf on December 14, 2015, 06:48:40 amThis was never actually proven and that announcement didn't actually stem from Nichicon, it stemmed from a university in Iowa:QuoteI think they were of the assumption that they were "overfilled" because they were leaking an overabundance of electrolyte. Nichicon never actually commented on the defective HMs and HNs. Any announcement (at least that I could find on the Internet) that the problem would be "fixed" came from Dell.QuoteNope. The follow up article to that issue shows Sanyo denying that they supply Jamicon with electrolyte:http://old.passivecomponentmagazine.com/files/archives/2002/PCI_02_06Nov-Dec.pdfI'm sure many of those bad bands, IE Teapo, Lelon, OST, G-Luxon, and Jamicon, were lying so as to protect themselves. It's very unlikely they pay the higher premium for importing higher purity materials from Japan - they can't even be bothered to QC test their products.QuoteYup, those are terrible. The Proadlizer capacitor (of a tantalum polymer class) was manufactured by Chemi-con and NEC as a joint effort. I don't know what exactly went amiss during the manufacturing process. Maybe the polymerization process was ineffective, IE residue could have been left over on any of the layers of functional polymer on the cathode (possibly using polypyrrole), creating a leakage path which grew over time (especially with high heat and humidity) and resulting in all those failures. Just a theory of course...QuoteCheaper brands use very bad materials and faulty electrolyte, so faulty that such capacitors could actually bulge in a sealed bag (as shown in this thread with those CapXon LZ capacitors), in a cool and dry environment, retaining their full leads, without ever having been soldered to a board, or without having bias applied to the plates or conducting current (although heat can certainly expedite such chemical reactions). Really bad brands use shoddy quality aluminum foil (with purity below 98%, the minimum specified by DAPO), which contains an excess of copper, zinc, magnesium, and iron, and that can certainly cause hydrogen gas to form at the cathode.Quote from: blueskull on December 13, 2015, 06:16:00 pmRubycon YXA are good, general purpose capacitors (although PX has indeed replaced them for some time). You just need to use them properly, IE within specifications. Lelon has always been a terrible brand - one of the primary brands associated with the so-called "capacitor plague".Quote from: mikeselectricstuff on December 13, 2015, 02:47:42 amNo, not really, unless you're referencing KZGs and KZJs (those are also known to bulge in storage).But CapXon is a terrible brand. No brand has a higher failure rate in LCD monitors.QuoteThe higher voltage generates the dielectric film on the anode faster and keeps it thicker, which prolongs the thinning of the dielectric, IE the H2O base electrolyte's tendency to attack the aluminum oxide layer, convert the aluminum into hydroxide, and outgassing thereafter. The problem with cheap brands is that the water-base electrolyte that they use does not contain the proper hydrogen absorbers, corrosion inhibitors, depolarizers, and conductivity enhancers to stabilize the oxide film and suppress the aggressiveness of that type of electrolyte. That type of electrolyte needs very pure materials, good manufacturing (effective QC testing), and excellent additives to remain stable. So it's not IF but WHEN those bad capacitors fail. Of course, there is more to it than that - it's critical that the electrolyte has a chemical composition that isn't bound to wreak havoc upon the rest of the materials. pH values are also vital, because too high a pH value (higher than 7) and the electrolyte becomes basic rather than acidic, which means they are more chemically prone to instability.But without question, QC testing is the most important factor of all, and that's what most cheap Taiwanese and Chinese brands miss, and that is the reason for their inconsistency and unpredictable performance in the real world. The Japanese brands process all their own materials (which are always of high purity and quality) and perform extensive QC testing on all (if not most, possibly evidenced by the defective KZG, KZJ, HM, and HN series, unless they were counterfeit) of their capacitors. Most cheap brands don't bother with QC testing at all, so whatever defects that are present in their products won't actually show up until some time after they're manufactured, IE when they reach the consumer and when it is no longer those companies' problem.As for the Lelons that survived reverse voltage? It would make sense if they were bi-polar electrolytics by any chance. OR, if Lelon made a mistake and sleeved those capacitors with the polarity stripe the wrong way around from the factory (more likely the latter). Or possibly because they were installed on a negative output. No electrolytic that isn't bi-polar can survive reverse polarity for long, not even the highest quality electrolytic of sorts (unless they're semi-polar). Reverse polarizing capacitors exceeds the reverse bias (cathode) voltage, which usually isn't higher than 1.5V. And just to be clear, all wet electrolytic capacitors have some sort of wear out mechanism. The liquid electrolyte is prone to giving away and drying up over time, whether through rubber seal diffusion or through the self-healing mechanism. But there is certainly a difference between the top tier brands and the lesser quality ones.

author: wagon
author_rank: Frequent Contributor
timestamp: February 12, 2016, 12:03:59 am
content: I noticed 'Rubycon' being put up as a reliable brand... in the 1990's Mitsubishi Electric used millions of them in their automotive electronics. I've replaced probably thousands of them after they leaked their guts or exploded. Whatever model cap they were, they were crap. But good for business. (Some of the failures were under 5 years of vehicle operation, so not a lot of hours)

author: Wester547
author_rank: Newbie
timestamp: February 12, 2016, 01:05:52 am
content: ^ There was another "capacitor plague" of sorts in the late 80s and early 90s known as the "Quaternary Ammonium Salt / Compound" issue. The problem was not in the organic solvent (usually either ethylene glycol or gamma butyrolactone) but in the solution (the quaternary ammonium salt system), where over a period of time (even on the shelf) the solution would harden and turn to a caustic, acidic substance, and the rubber bungs and lead wires were no longer sufficient in sealing the electrolyte so it leaked from the bottom and tended to corrode traces... this was a massive issue in automobile ECUs from the late 80s and early 90s.The problem was severe enough for Chemi-con to issue a notice on the matter (attached).The series that were affected from the "top tier brands" are:Nichicon - PF, PA (not the new series from 2006), PB, PR, PL, PY, PQ, PC, VZ, VT, RZ, RT, PGChemi-con - LXF, SXE, TXF, SXF, SXGRubycon - YXB, YXC, SSP, and possibly a few other seriesPanasonic - NHE (GE series), HFQ, HFS, HFEElna - RSH, RSG, RSE, RC2S, RC3SAll of the affected series are rated from -55C to +105C in their datasheets. The quaternary ammonium salt system is not used in electrolytics anymore, with the exception of double layer electrolytics.

author: nctnico
author_rank: Super Contributor
timestamp: February 12, 2016, 01:06:36 am
content: Quote from: Wester547 on February 11, 2016, 11:15:32 pmI actually have such a Dell GX270 and after replacing the capacitors it worked fine for another 5 (or so) years running 24/7 after which the capacitors needed replacing again. IMHO the root problem is not the capacitors themselves but more likely heat and/or a large ripple current which puts a lot of stress on the capacitors. Some batches maybe overfilled making the capacitors prone to early failure but there sure is a problem in the design of the onboard power supply as well!

author: ktulu
author_rank: Regular Contributor
timestamp: September 05, 2017, 08:45:18 am
content: Hello.I need to replace all the leaky electrolyte capacitors in a nice Sony SW77 radio. The only problem is, that unfortunately all the supplyers nearby only sell chinese brand caps. (Samxon, Capxon etc...)Question is, should I use these, or rather remove some old used, but good brand caps (Rubycon, Nichicon, Panasonic...) from some boards that I have laying around? (which measure good both on capacitance and ESR)

author: wraper
author_rank: Unknown
timestamp: September 05, 2017, 09:25:55 am
content: Quote from: ktulu on September 05, 2017, 08:45:18 amSamxon is fine. And in general there is no much problems with Chinese capacitors if they are not LOW ESR and working at high ripple current, like in SMPS. Don't use old caps, some may have no much life left in them. Yes, capacitors made by 1st tier companies do fail too.

author: ktulu
author_rank: Regular Contributor
timestamp: September 05, 2017, 10:21:10 am
content: OK, thanks. I will buy new capacitors then.

author: rsjsouza
author_rank: Super Contributor
timestamp: September 05, 2017, 03:34:03 pm
content: Just to confirm what wraper have said. Samxon and Capxon capacitors have come a long way from the older issues discussed earlier in this thread - they are not top quality, but don't fare bad on a comparison. As anecdotal evidence, I recently disassembled three 11-12 year old LCD screens (Viewsonic and Samsung) with Capxon and Samxon that just recently have developed issues due to their leaking capacitors on the low voltage side of the switching power supply (the large tank capacitors are still absolutely fine). The monitors were used about 8-10 hours per day during these years. I call this quite a decent endurance.