Capxon reputation and demonetization

[Ice-Tea]

Is it possible extremely low voltage parts are more prone to failure because bad designers are more tempted to not provide adequate margin i.e. use 6.3V parts for a 5V supply rail?

That's *exactly* why 6V3 caps exist: 5V rail +/- 5% accuracy = 5V25 + 20% derating is 6V3. This is by design.

I was under the impression that ideally a greater de-rating factor than 25% should be used, when selecting capacitors: >50% or more being ideal.

Come to think of it, perhaps I'm over cautious? The above rule is more important with tantalum capacitors which do need to be generously de-rated. Aluminium capacitors should be fine pushed closer to their maximum ratings.

Depends. If you want to make stuff that will last untill kingdom come, derating more is obviously a good idea. Not because its needed but because whatever margin you add may buy you a bit more time somewhere. But in high volume customer electronics, this is common. Same with 6V3 ceramics: they exist for the express purpose to be able to put them on 5V rails.

Obviously not something you want to do if there's a fair chance of transients. But well regulated DC/DC? Why not...

[T3sl4co1l]

Did you actually read what I wrote? That devices still work after a decade passed since capacitor replacement.

Replaced with what?  Guessing you chose something rather more robust (and expensive, were it used in original design).   Cap spec is part of the design!

Ed:

This is about crappy caps, not ratings. Good quality capacitors with similar ratings (ripple current, lifetime) placed instead of crappy capxons which failed after 2 years are working a decade later without an issue.

Highlighted keywords -- if this is the case, clearly one of them is rated incorrectly (or, perhaps rated as worst-case rather than average-case lifetime?).  I haven't seen the stats from each manufacturer, if this is the case (there is unfortunately very little that manufacturers make public about their inner process and quality..).  There's also weasel words, like reading your example overly strictly: i.e., just matching ripple current and lifetime, not also impedance and temperature.  In which case, it's likely not even your fault, as it's hit-and-miss whether they give impedance spec at all. :/

So, I'm probably just being a dick, or it's manufacturers not giving out enough information to adequately specify their parts.

Tim

[wraper]

Did you actually read what I wrote? That devices still work after a decade passed since capacitor replacement.

Replaced with what?  Guessing you chose something rather more robust (and expensive, were it used in original design).   Cap spec is part of the design!

In PC monitors usually Samwha WL, Samxon GT or Jamicon WL. (Samwha WB and Samxon GF were affected as well)

Highlighted keywords -- if this is the case, clearly one of them is rated incorrectly (or, perhaps rated as worst-case rather than average-case lifetime?).

Have you ever heard about capacitor plague? The fact a lot of crappy capacitors were made is the reason a website like badcaps exists.

For example crappy Capxon GF, KF, GL http://www.amelec.ch/tl_files/amelec/downloads/capxon/gf.pdf are rated for 5000 hours with 10+mm diameter.

Actually there were like 2 waves of this crap. First in early 2000's there were crappy motherboard caps made by evercon(GSC) and some others. Then followed in mid 2000's by tons of dying PSUs, monitors, TVs and other equipment with much wider list of different capacitors failing.

[Conrad Hoffman]

There was a time when far more technical data was available from manufacturers. In hindsight, maybe they gave away some competitive advantage by saying too much. Anyway, pay particular attention to TP-64-11 and 62-4 here- http://www.conradhoffman.com/lib_item_list.htm

Though quite old, the technology hasn't changed all that much for standard electrolytics. It's interesting that they note the shortened life of low voltage parts. IMO, those parts exist entirely for reasons of physical size, and we've made some good strides in that area. I always replace old low voltage parts with 16 volts or more, as the sizes are often the same. In some cases the modern parts are even smaller.

[T3sl4co1l]

Actually there were like 2 waves of this crap. First in early 2000's there were crappy motherboard caps made by evercon(GSC) and some others. Then followed in mid 2000's by tons of dying PSUs, monitors, TVs and other equipment with much wider list of different capacitors failing.

Two different things -- if they don't meet mfg spec, that's their fault.  That's why "capacitor plague" was a thing (and probably will be again, alas), not /just/ a symptom of short-life design.

If the design of a product doesn't meet your expectation, that's your fault (caveat emptor)*.

(*As shitty as that is, but that's how it is.  Notwithstanding consumer protection laws, where applicable, which helps!)

Tim

[wraper]

That's why "capacitor plague" was a thing (and probably will be again, alas), not /just/ a symptom of short-life design.

If will happen, likely with different parts. It was everyone jumping on LOW ESR bandwagon with water based electrolyte without proper development and long term testing.

[Conrad Hoffman]

Note that the water problem was talked about in the papers I referenced. A mere 50 years ago!

[Costas07]

Just checked my supply of capacitors for CapXon and here we are - they were just staying on the shelf since 2011-2012.
ESR meter shows increased resistance and triple value of nominal capacitance.

[Zero999]

Does anyone know why unused capacitors popped? Presumably some sort of chemical reaction occurred inside the capacitor, which doesn't require any current to flow.

I'm not aware of any lawsuits against these bad capacitor manufactures. At the very least those who purchased their products should get refunded.

[janoc]

Are we resurrecting a 6 years old thread?

[Zero999]

Are we resurrecting a 6 years old thread?

Why not? There still plenty of these crappy capacitors around.

[floobydust]

The missing secret sauce in the electrolyte was an anti-corrosion additive. Surprised to see those corrode so bad just in storage.

Capxon was privatized on Oct. 2020 and was de-listed by the HK exchange.
There are many scam chinese component companies that get on the stock exchange, registered in the Caymen Islands, load up on investor dollars.
Next is the pump'n'dump and then close down once everyone realizes the parts are crap, accounting irregularities etc. Rinse and repeat.

Capxon group looks legit? and it could be that they are heavily counterfeited. But I've never seen one last, ever...