Why doesn't everything use solid aluminium capacitors? (2025 Update)

They're polymer capacitors (polymer takes place of liquid electrolyte) and are used selectively in equipment. See the second picture down on the right, for a typical appearance. They lack pressure relief seams.

In your TV set, the components are not exposed in the same way. Marketing consists of "look, thin bezels", or "now with built in spyware". No mention is made of what corners are cut in the power supply section. If you look at LCD monitors and the power board in there, the absolute cheapest manufacturing is used for the power board (sorta the equivalent of what you'd find in a $20 ATX PSU).

There is nothing wrong with electrolytic capacitors if they're made properly. Consequently, just because you find a cap with a pressure relief pattern embossed in the top of the cap, is no reason to panic.

It's hard to say whether any scumbag is still making caps using that stolen/incorrect electrolyte formula.

And as to "why do people continue to do bad things", it's a calculus. "Will I be executed or put in jail?" That's the question they have to ask themselves every day.

"22 May 2019 Ozone layer: Banned CFCs traced to China say scientists"

This is copied from the web page of a capacitor company.

Pros of aluminum electrolytic capacitors:

Higher voltage ratings available (up to 600V) Way cheaper pricing (for the same capacitance and voltage) Better leakage current behavior than polymer

Pros of polymer electrolytic capacitors:

Lower ESR/higher allowable ripple current No dry-out behavior (unlike aluminum capacitors) Higher expected lifetime/load life

And while one biased company claims electrolytics dry out after 3 years (a made up number), another company (likely using field statistics for their own capacitors) finds the time constant is 17 years. And I would have to conclude that the 17 year number is likely to be closer to the truth (based on old computers still in a running state, like my first computer from

The Arrhenius effect is for real, and operating even the best electrolytics at high temperature, doesn't end well. At the highest allowed temperatures, some of these electrolytics (by calculation) should only last for 2000 hours. That's what the curve fit data for accelerated life testing shows. When I say a number like 17 years, it would be in an item with proper and copious cooling. Note that electrolytics themselves get warm in service, depending on the ripple current being forced through them. The plastic sleeve on the outside, does not enhance cooling for those situations. The capacitors in VCore (on the primary or secondary side) could be experiencing high ripple currents. And if any are to fail, those should go first. The "bulk" decouplers placed near a PCI or PCIe slot, those aren't under nearly the same stress level.

HTH, Paul

ANd the counterfeit chinese electrolytics that were causing the big problems are ancient history. (1997 to 2007, more or less) If your equipment is 13 years old and hasn't failed yet it was built with genuine parts. The "solid aluminum" capacitor uses a non-liquid polymer or Manganese Dioxide as the dialectric in place of the liquid (generally ethylene glycol or boric acid based) electrolyte. They have the advantage of much longer life as the dialectric is not reactive with the aluminum and they don't dry out or boil inhigher temperatures. The "problem" electrolytics were a result of a stolen recipe for the electrolyte which had been sabotaged - the theif didn't get the "real deal". The defective product was widely sold "for a good price" to manufacturers around the world and the result was a HUGE rash of electronic product failures over a roughly 10 year span.

Er.... wasn't it genuine parts from Nichicon?

Yip, I repaired about 100 motherboards from Dell computers in about 2009. The other 100 were in extended warranty, but 100 I replaced the capacitors to save a lot of money.

Which means every capacitor should be that type. They have superceded the others.

Not what I heard. I heard two stories. One was that the capacitor manufacturer made a mistake. The other was that the designers (eg Dell Computers) were cost cutting too much and used capacitors right at their limit of current and temperature.

The chinese f*ck their customers every chance they get.  The capacitors are just another example.

#1 Would not explain why so many cap manufacturers had the problem. #2 would not explain why virtually ALL asian producers had the problem and the few that didn't use the bad caps - and even the models made pror to the problem or after the problrm used the same specs.

They (the capacitor manufacturers) had a chance to buy a lower cost material to save some money and didn't QC it well enough - and they got bitten. Then their customers got bitten.

I worked for a computer manufacturer at the time. The stolen formula is the real story. The formula stolen was "defective". The counterfeit electrolyte was sold to capacitor manufacturers across Asia - including some of the "prime" Japanese suppliers IIRC there were two? asian (japanese) capacitor manufacturers that never used any of the bad stuff - all the rest got bitten at least once. I think the Koreans largely avoided the problem too. (The Lucky Gold Star monitors seemed to survive - now called LG) Virtually every motherboard built in China or Taiwan at the time had bad caps. Most of the ATX power supplies did too.Sony camcorders virtually all had bad caps, as well as the majority of monitor power supplies. IIRC a large component manufacturer had to get out of the capacitor business - almost bankrupted the whole company.

IIRC Packard Bell Computer co failed over the issue and was "rescued" by HP.

Temperature, both rated and operating, is a factor. As I understand it a rating of,say, 7000 hours at 105C means for every 10C lower actual operating temperature it doubles the lifetime. Operating them at 65C will give approx 12 years of continuous use.

In a old computer the power supply always had it's own fan keeping the unit relatively cool. In modern TVs, set top boxes etc the room for a noisy fan giving a decent air flow is somewhat limited and temperatures within many boxes are 60C+. Many capacitors in switched mode supplies also seem to be fitted very close to hot heat-sinks! In my experience it's usually the power supply capacitors that have an early failure.

Some manufactures will fit capacitors rated at 7,000 hours at 85C so when operating at 65C the life expectancy is closer to 28,000 hours (3 years continuous use).

There is also a problem with life expectancy from self heating due to the Equivalent Series Resistance (ESR). For a switched mode supply a capacitor with a low ESR is required. A decade or so ago I read a technical report from one of the more respected capacitor manufacturers (Rubicon I think) where they claimed that they used physically larger cans/packaging than some of their Korean competitors to ensure lower ESR figures. I always found that when changing duff electrolytic with Korean brand names such as SamYoung etc. that the replacements from a variety of reputable brands were physically larger - usually the same diameter can but the height of the can was maybe 5mm more.

I've had capacitors fail in a couple of PVRs after a couple of years but carefully selected replacements lasted close to 10 years.

I was sort of lucky in that I sent 2 mother boards back under warrenty and got them replaced when the capacitors failed too soon. They sent me a new box with connectors and all.

It is not only the cheep or China parts that fail. I have a couple of pieces of HP test gear that I bought surplus that the capacitors have failed in the power supplies. They origionally sold for about $ 50,000 each back in the mid 1990's. I guess that about 20 years is not too bad for them. Not sure how many hours they may have had on them.

Even HP used asian caps and got stung with the defective stuff.