Electrolytic Capacitors – an Electronics Industry Scandal?

One of the commonest causes of failure of electronic products brought into Repair Cafés is a failed electrolytic capacitor. Electronics has a bad reputation for being short-lived, and this is evidently a major part of the reason.

Aluminium electrolytic capacitors are common and inexpensive electronic components. Every switched-mode power supply has several, and the average hi-tech product contains dozens. They are an indispensable part of electronic design.

Are electronics manufacturers knowingly producing products that have a short product lifetime? It is very hard to argue otherwise.

The lifetime of an aluminium electrolytic capacitor is variously quoted at 1000, 2000 or 3000 hours of operation – that’s not very long!! (3000 hours is only 4 months!) The reality is usually significantly in excess of this, but nevertheless it is one of the commonest causes of electronic product failure.

The problem is that there are few alternatives. Tantalum capacitors were heralded as the answer some years ago, but tantalum is produced from the mineral coltan, which is largely found in central Africa. Mining of coltan is associated with exploitation of local populations by large mining conglomerates, and it is rare and expensive. A tantalum capacitor costs roughly sixty times the cost of an equivalent aluminium capacitor – so they are only used where space is at a severe premium.

Unfortunately, for small electrolytic capacitors there seems to be little research happening to find better alternatives. This is in noted contrast to the research happening around the world into utility-grade energy storage in large supercapacitors.

I think it would be helpful for Restart Parties, Repair Cafés and other environmentally-concerned groups to highlight this issue, and lobby for research into inexpensive but longer-lasting alternatives.

Chris Moller, C.Eng, MIET, 11May2020.

References

Aluminium Electrolytic Capacitor - https://www.sciencedirect.com/topics/engineering/aluminium-electrolytic-capacitor

What is expected life of Electrolytic capacitor? - https://en.cosel.co.jp/technical/qanda/a0026.html

Research on failure prediction method of electrolytic capacitor used in power conversion circuit - http://en.cnki.com.cn/Article_en/CJFDTotal-DZIY201001008.htm

Coltan - https://en.wikipedia.org/wiki/Coltan

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I have been directed to check out the the Nippon Chemi-Con KZN series, which are rated 10,000 hours - well, at least that’s over a year!

There are also polymer electrolytic capacitors that are more expensive, but some are rated at 20,000 hours. However, I’m pretty confident that any electronic product I buy on the High Street won’t have been manufactured with these!

I didn’t realise the rated lifetimes were so low, that’s quite frustrating.

Interesting to think about the origins of tantalum, too. I suppose that with tantalum capacitors being so under-used at the moment then any improvement in product longevity would be far outweighed by misery from increased tantalum demand.

I would say that electrolytic capacitors are “only” a significant minority of the electrical repairs I do. I see a lot of SMD diode failures in LED circuits, and no shortage of transformer failures too, from what I can diagnose.

At least electrolytic capacitors ARE very replaceable once the device is open. Replacing a transformer is effectively impossible due to availability of identical footprint components and replacing SMD components is harder, especially when they are nestled under other components as they often are in LED bulbs.

As an aside, it’s hilarious to see LED bulbs still claiming many thousand hour lifetimes despite almost all of them having electrolytic capacitors inside!

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Hi Guy,

Fortunately, the quoted lifetime for electrolytics is at rated voltage and temperature (either 85’C or 105’C). Conservatively rated capacitors should last
longer – but what manufacturer has the incentive to put in larger and more expensive capacitors than really necessary?

High ripple current (which causes internal heating) can also make the temperature higher than ambient).

What prompted my note: I’ve just tried to repair a flat-screen TV – but after replacing four electrolytics, each running with 0-20% of their rated value, the
TV still didn’t work, so there are probably more.

(BTW, I highly recommend the LCR component testers available on eBay for around £16. Incredibly, I’ve checked mine against known-good capacitors 22pF - 1mF,
inductors 20uH to 100H and resistors 0.2ohms to 50Mohms. Also excellent on MOSFETs, transistors, LEDs etc.)

Chris

Thanks for sharing, @Chris_Moller. (Previously my main source of info on this was https://www.badcaps.net - forum and website run by an activist in small-town Missouri. I think @Ten told us about it years ago.)

For the past couple of years, we’ve carried a set of common capacitors to events, but I can’t honestly vouch for their quality. We have definitely had a chance to use them.

I think this might make an interesting guest blog post for our website, Chris! (Or we could write it together.)

Should we take a look at our data, in light of what you shared? I’ve searched our repairs database for “cap” which seems to cover all of the permutations of cap / capacitor / capacitors. 99 entries.

caps.csv (32.3 KB)

I have a hunch that most of these repairs are not finished, and almost all of them require followup. We don’t yet have a way to link repair records to track the outcome, although this is something in discussion. One of the follow-up cases I do know about was an inspiring capacitor repair featured in BBC coverage earlier this year.

Hi @Janet,

I struggle with taking electrolytic capacitors to events, as even within a single value and voltage, there are short stubby ones, tall thin ones (radial) and
axial ones, and often space is limited, particularly in power supplies. For smaller values, there are also surface-mount ones. Generally speaking, replacing a capacitor with the same value rated at a lower ESR, higher working voltage and 105’C temp is good
practice to stop it failing again – but it will probably be larger. (Beware that smaller capacitors may have a higher ESR (equivalent series resistance), and this may be critical in power supplies. The ESR is not printed on the capacitor – it’s only available
in the data sheet.)

Interesting that badcaps.net has created a list - but I wonder what percentage of replacements that covers?

The situation is different with safety filter capacitors – we take a stock of X2-rated safety capacitors, but probably to be safe, we should take Y2 instead
– usually with a capacitance of 100nF.

Thank you for the BBC link – I missed that first time round.

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@ten?

And anybody else interested in diving into this data? :diving_mask:

I think we can safely exclude “laptop keyboard - Faulty keys and missing caps…” from the capacitor faults list :slight_smile: and “CAPS button” maybe?

What proportion of restart’s electronics fixes are these 97?

I’ll go through and try to guess whether they might be electrolytic or other types. For a repair event, capacitor failures are a pain - they can be difficult to diagnose and that means it takes time and suitable equipment, and you never have the right spare part. That practical aspect of diagnosis is a topic I’d be interested in learning more about @fixfest?

A bulging top of an electrolytic is a pretty reliable giveaway. (Failed safety capacitors usually show obvious charring or worse.) Occasionally, there is no trace left of the failed component - just some mess elsewhere on the board!!

The tester I mentioned above is brilliant for testing all capacitor types - but the component has to be removed from the circuit first.

So a quick sweep through these gives:

  • 19 not capacitor-related (but they include “cap” as in capacity/capability/…)
  • 4 could be capacitor-related but not clear in what respect (e.g. caps were changed but that didn;t fix the problem)
  • 12 are maybe low-voltage capacitors e.g. on the regulated side (e.g. hum on speakers)
  • 14 are possibly AC suppression capacitors (smoking device)
  • 50 are likely high-voltage DC (e.g. 400V-ish smoothing on the live side of a switching PSU)

It’s all a mildly educated guess and I will happily accept advice to change my categorisation. In particular I’ve never seen a smoking device so it’s a guess that the problem is likely to be protection caps, on the basis that electrolytic caps usually go low value/high ESR which isn’t likely to produce smoke.

I don’t seem to be able to attach my updated CSV file.

UPDATE: Here’s the updated CSV - a few extra columns added with totalisators at the bottom:
caps_ian.csv (33.1 KB)

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This is great, Ian! :+1:

I’ve changed a setting in the backend, so you should now be able to upload the CSV without issues.

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Hi @Ian_Barnard,

Thanks a lot for this. @Monique has created a google sheet so everyone can go and comment specific entries.

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I have an ESR (Equivalent Series Resistance) meter that can easily check if an electrolytic capacitor is still good or not.
And quite often it can check it without unsoldering the capacitors from the board.
It is homemade by a friend, based on a “Nuova Elettronica” (an old Italian electronic magazine) project.
I wish to create some board to build some of this kind of ESR meters, with Restart Project Logo, to share with Restarters. I wish to share the project, the boards, the kit, and the complete ESR meters.
It could work stand-alone (with a microAmperometer) or coupled with a multimeter (it use a microamperometer as scale, 100 mA is good, 80 mA is bad).
I work in a microelectronic fab, and I will have access to an internal FabLab, where I could develop this project.
I wrote to Kyle Wiens of iFixit that seems to be interested in this project.
I hope someone is really interested and maybe can help me, I have too much interests and my free time is over.

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Hi @Sergio,

That’s a great idea. I can easily see how it works – I wish I had thought of it! I imagine with a bit of publicity on Restarters.net and perhaps some crowdfunding,
we could build a batch, or create a DIY kit. Can you share some details?

Yes, I try now to put the article here. It is in Italian but the schematics are in an international language.ESR_NuovaElettronica.pdf (2.4 MB)

It works at very low voltage so the active components are not involved in the measure.
And it permits to add 2 opposite diodes in the input, so if the capacitor is full you don’t risk to burn the circuit.
I think it is a great circuit. Quite old but still very useful.

It’s true that electrolytic capacitors are one of the main points of failures of electronic assemblies. But saying that OEMs design product intentionally with a short lifetime might inaccurate.

Cost is one of the main drivers in pretty much every industry and electrolytic capacitors are cheapest.
Tantalum capacitors are more expensive and they suffer other important failure modes under overcurrent and overvoltage. that can lead to overheating and ignition. So, not, they are not a direct replacement for electrolytic capacitors.

They are other types of capacitors like the new aluminium polymer capacitors. But they are far more expensive.

As always, the reality is more complex than we would like it to be.


I thought it was commonly accepted that industry knew about this widespread problem in the early 2000s and did nothing about it. Given that industry paid no real price for its faulty caps, now the issue appears to be the fine line between planned obsolescence and cost-cutting. They can continue to use sub-standard capacitors in the name of price-sensitivity of consumers, when in fact it also serves the useful purpose of reducing product lifetimes.

Quoting Bad Caps:

How did this happen?
The reason this problem exists is because of a large-scale industrial espionage foul-up. Some companies decided to steal an electrolyte formula from another competitor. Little be known to them, the stolen formula was incomplete and flawed. They didn’t discover this until it was too late and they had manufactured and distributed literally MILLIONS of these flawed capacitors. It was way too late for any kind of recall, and even today, these crappy components are being used in new boards. As I mentioned before, I believe this problem runs much deeper than simply an industrial espionage screw-up, as that incident was exposed years ago, and the problem still exists today. Nowadays, it just boils down to corporate bean counters cutting corners to save money by using shoddy components.

The cause…
This inferior and flawed electrolyte formula was used by a number of component manufacturers that sold to many different, reputable, and well known motherboard manufacturers. This problem isn’t isolated to one particular brand of motherboard, and not even isolated to motherboards alone. I won’t mention brands, but a VERY popular monitor manufacturer has been plagued with RMA’s on some of their monitors that were built using these inferior capacitors. This problem has been reported in computer motherboards, monitors, televisions, radios, and stereo equipment. Through my experiences owning a service center, I’ve personally seen and serviced a large number of ‘high-end’ equipment that had prematurely failed capacitors.

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Hi @Chris_Moller, @Sergio and everyone else,

When it comes to replacing capacitors in TVs and other products, what are the main barriers you’re experiencing?: It’d be helpful to know if any of the following are relevant issues

  • Accessing specific replacement capacitors - is this an issue, or are they mostly generic components?
  • Assessing the correct specs of the capacitor that needs replacing
  • Accessing the schematics of the device to perform the repair
  • Assessing which capacitor(s) needs replacing
  • Anything else?

The reason I’m asking is that as part of the European Right to Repair Campaign, we’re following developments of European ecodesign policy on electronic displays, due to come into effect in 2021. Replacement capacitors were originally meant to be made available by manufacturers to (professional) repairers , but there’s a proposal to remove this requirement, allegedly because capacitors are standardised, widely available components. We want to make sure this is indeed the case, and whether removing this requirement might have other negative consequences with regards to the repair information supplied by manufacturers about these parts.