4 ms·

Because of that drama, I remember some people (maybe me included, not sure anymore) actually thinking that electrolytic caps just generally had a pretty bad lif

by anyfoo 4y ago

Because of that drama, I remember some people (maybe me included, not sure anymore) actually thinking that electrolytic caps just generally had a pretty bad lifetime, and the need for replacement was just reality for products that were expected to last for more than an unreasonably short lifetime. Only later did I learn that it actually seemed to have been industrial espionage gone wrong! https://en.wikipedia.org/wiki/Capacitor_plague https://en.wikipedia.org/wiki/Capacitor_plague That's probably also the reason why so many retro enthusiasts just generally "re-cap" almost everything they touch. In a lot of cases, you just don't need to do that, and sometimes it could be worse to replace capacitors not affected by the capacitor plague: Any factory adjustments made to the device could well depend on the exact characteristics of the capacitors that were present in the device when it was manufactured.

KennyBlanken 4y ago
Electrolytic caps (especially aluminum) do generally have a pretty bad lifetime. Their specs (capacitance, and internal resistance aka ESR) degrade significantly over time, non-linearly, as temperature (and voltage) go up. At their rated voltage/temperature, lifetime maybe be ten thousand (or less) hours...barely enough to last a full year of 24x7 operation. This is one reason mining GPUs can be a questionable buy. The miner may have operated them at "low" temperature, but they were on 24x7, whereas a gaming PC may be only on a couple of hours a day a few times a week. Ultimately it comes down to how much the designers overspec'd components and/or factored in for wiggle room and how much the capacitors can degrade before circuits start acting up enough for the user to notice.
- TedDoesntTalk 4y ago
  > a gaming PC may be only on a couple of hours a day a few times a week Never met such a gamer
  - zabzonk 4y ago
    a gamer with a career and a life outside of "gaming"?
    - Dylan16807 4y ago
      Doesn't mean you turn anything off.
  - coryrc 4y ago
    More seriously though, lifetime of a component is generally halved for each ten Kelvin increase. So idling or lightly taxing the card at, say, 60°C instead of 90°C is a 8x longer lifetime alone.
- anyfoo 4y ago
  I corrected my text above to read "unreasonably short lifetime" now. In my experience, plenty of products from the 90s and older still seem to work absolutely fine despite their use of electrolytic caps. Yes, some of their parameters may have degraded, but it still seems to be within tolerance for their particular use in the design. It also depends on how exactly the caps are used. Caps close to a massive heat source, like a power resistor, are likely to dry out relatively quickly, while others, like those used as part of small signal filters, may last literal decades, with not much change in e.g. ESR or capacitance (and hence still conform to factory calibration pretty okay). Admittedly I don't have any hard data for that, only anecdotical experience with measuring ESR and capacitance and saying "this looks fine". The crucial point is that the "capacitor plague" affected much more than products which were on 24/7 or which had tight tolerances, to the point where it was very well visible to the "casual" consumer. Yes, we may not expect a server mainboard that was on for the last 20 years to still have its caps within spec, but wrt the capacitor plague, the gaming PC you mentioned would have been quickly affected, in an obvious manner, as well.
  - coryrc 4y ago
    > while others, like those used as part of small signal filter I wouldn't expect those to be electrolytic, though. Electrolytic capacitors are mostly used when the exact characteristics are not important, like on a supply bus, where your qualifications are typically either "at least" or "no more" than some value. Tripling capacitance usually has no negative effect on a supply bus but huge change of doing signal conditioning, so something like that is more often going to be a capacitor that is intrinsically more stable.
    - anyfoo 4y ago
      Good point, but in audio applications for example, for cross-over filters, bipolar electrolytic caps are common. The “calibration”, if any, may be very simple, though.
- kqr 4y ago
  > lifetime maybe be ten thousand (or less) hours...barely enough to last a full year of 24x7 operation. Wait, how many of these are in a typical consumer computer? Even if it's just 20 or so (I truly have no idea) I don't get the numbers to add up. I've run, say, 6 computer-years worth of capacitors with no problems -- under the assumption above this would be 120 capacitor-years. Let's say at this point there's a 50--50 chance I would have experienced problems (this is not a rigorous survival analysis, of course, just something to get started). If a single capacitor has a lifetime of just one year, then "lifetime" must be defined as the solution to p^120 = 0.5 which is p=99.5 %. Is it correct that when one speaks of the "lifetime" of capacitors one refers to the point where 0.5 % of them no longer work? If "lifetime" means 50 % no longer work then I would seem to have been extraordinarily lucky (I'm the 10^-35 %!!) -- I don't hold that for very likely. What else am I missing?
colechristensen 4y ago
> Any factory adjustments made to the device could well depend on the exact characteristics of the capacitors that were present in the device when it was manufactured. Capacitors especially and in general most components age and their specs drift. This is not a valid reason for not replacing components. If something isn’t actually all that old, sure, but capacitors especially are just not precision components over long periods.
- anyfoo 4y ago
  For one, electrolytic capacitors can have pretty large tolerance for their initial value. The question then is also whether a fresh cap’s value is closer or further away from the value the old cap initially had compared to what it drifted to. More generally however, you just don’t need to replace a capacitor in something that works well and that is not anticipated to break catastrophically because of the capacitor plague. If the caps do eventually drift off so far that it affects operation, replace it then, and then it makes sense to take the opportunity to replace others as well as precautionary measure. Sometimes you know that a non-plague cap will likely fail because it’s right next to a massive heat source, and you may replace it early with good reason. But sometimes I see people literally replacing 80 caps or more without reason, when I have the same device sitting at home with its original caps, still doing its job well within spec for years.
dmix 4y ago
> Only later did I learn that it actually seemed to have been industrial espionage gone wrong! The relevant bit from Wikipedia: > Industrial espionage was implicated in the capacitor plague, in connection with the theft of an electrolyte formula. A materials scientist working for Rubycon in Japan left the company, taking the secret water-based electrolyte formula for Rubycon's ZA and ZL series capacitors, and began working for a Chinese company. The scientist then developed a copy of this electrolyte. Then, some staff members who defected from the Chinese company copied an incomplete version of the formula and began to market it to many of the aluminium electrolytic manufacturers in Taiwan, undercutting the prices of the Japanese manufacturers. This incomplete electrolyte lacked important proprietary ingredients which were essential to the long-term stability of the capacitors and was unstable when packaged in a finished aluminium capacitor. This faulty electrolyte allowed the unimpeded formation of hydroxide and produced hydrogen gas.
- winReInstall 4y ago
  Catalytic metals trace elements, that recombine those gases. Or else the hydrogen tunnels through all things, turning them brittle.. I sometimes wonder, how those secret sauces can remain so secret. After all, you have to order them in rather large batches every week, month, year..
  - deleted 4y ago
    [deleted]
gymbeaux 4y ago
I think the main reason enthusiasts recap is to prevent damage to the rest of board when the capacitors swell and leak. E: I can't believe something so easy to Google is being downvoted as though it's false info: https://www.reddit.com/r/retrogaming/comments/ib7nyh/replacing_capacitors_from_retro_consoles/ https://www.reddit.com/r/retrogaming/comments/ib7nyh/replaci...

by anyfoo 4y ago

KennyBlanken 4y ago

Electrolytic caps (especially aluminum) do generally have a pretty bad lifetime. Their specs (capacitance, and internal resistance aka ESR) degrade significantly over time, non-linearly, as temperature (and voltage) go up. At their rated voltage/temperature, lifetime maybe be ten thousand (or less) hours...barely enough to last a full year of 24x7 operation. This is one reason mining GPUs can be a questionable buy. The miner may have operated them at "low" temperature, but they were on 24x7, whereas a gaming PC may be only on a couple of hours a day a few times a week. Ultimately it comes down to how much the designers overspec'd components and/or factored in for wiggle room and how much the capacitors can degrade before circuits start acting up enough for the user to notice.

TedDoesntTalk 4y ago
> a gaming PC may be only on a couple of hours a day a few times a week Never met such a gamer
- zabzonk 4y ago
  a gamer with a career and a life outside of "gaming"?
  - Dylan16807 4y ago
    Doesn't mean you turn anything off.
- coryrc 4y ago
  More seriously though, lifetime of a component is generally halved for each ten Kelvin increase. So idling or lightly taxing the card at, say, 60°C instead of 90°C is a 8x longer lifetime alone.
anyfoo 4y ago
I corrected my text above to read "unreasonably short lifetime" now. In my experience, plenty of products from the 90s and older still seem to work absolutely fine despite their use of electrolytic caps. Yes, some of their parameters may have degraded, but it still seems to be within tolerance for their particular use in the design. It also depends on how exactly the caps are used. Caps close to a massive heat source, like a power resistor, are likely to dry out relatively quickly, while others, like those used as part of small signal filters, may last literal decades, with not much change in e.g. ESR or capacitance (and hence still conform to factory calibration pretty okay). Admittedly I don't have any hard data for that, only anecdotical experience with measuring ESR and capacitance and saying "this looks fine". The crucial point is that the "capacitor plague" affected much more than products which were on 24/7 or which had tight tolerances, to the point where it was very well visible to the "casual" consumer. Yes, we may not expect a server mainboard that was on for the last 20 years to still have its caps within spec, but wrt the capacitor plague, the gaming PC you mentioned would have been quickly affected, in an obvious manner, as well.
- coryrc 4y ago
  > while others, like those used as part of small signal filter I wouldn't expect those to be electrolytic, though. Electrolytic capacitors are mostly used when the exact characteristics are not important, like on a supply bus, where your qualifications are typically either "at least" or "no more" than some value. Tripling capacitance usually has no negative effect on a supply bus but huge change of doing signal conditioning, so something like that is more often going to be a capacitor that is intrinsically more stable.
  - anyfoo 4y ago
    Good point, but in audio applications for example, for cross-over filters, bipolar electrolytic caps are common. The “calibration”, if any, may be very simple, though.
kqr 4y ago
> lifetime maybe be ten thousand (or less) hours...barely enough to last a full year of 24x7 operation. Wait, how many of these are in a typical consumer computer? Even if it's just 20 or so (I truly have no idea) I don't get the numbers to add up. I've run, say, 6 computer-years worth of capacitors with no problems -- under the assumption above this would be 120 capacitor-years. Let's say at this point there's a 50--50 chance I would have experienced problems (this is not a rigorous survival analysis, of course, just something to get started). If a single capacitor has a lifetime of just one year, then "lifetime" must be defined as the solution to p^120 = 0.5 which is p=99.5 %. Is it correct that when one speaks of the "lifetime" of capacitors one refers to the point where 0.5 % of them no longer work? If "lifetime" means 50 % no longer work then I would seem to have been extraordinarily lucky (I'm the 10^-35 %!!) -- I don't hold that for very likely. What else am I missing?

colechristensen 4y ago

> Any factory adjustments made to the device could well depend on the exact characteristics of the capacitors that were present in the device when it was manufactured. Capacitors especially and in general most components age and their specs drift. This is not a valid reason for not replacing components. If something isn’t actually all that old, sure, but capacitors especially are just not precision components over long periods.

anyfoo 4y ago
For one, electrolytic capacitors can have pretty large tolerance for their initial value. The question then is also whether a fresh cap’s value is closer or further away from the value the old cap initially had compared to what it drifted to. More generally however, you just don’t need to replace a capacitor in something that works well and that is not anticipated to break catastrophically because of the capacitor plague. If the caps do eventually drift off so far that it affects operation, replace it then, and then it makes sense to take the opportunity to replace others as well as precautionary measure. Sometimes you know that a non-plague cap will likely fail because it’s right next to a massive heat source, and you may replace it early with good reason. But sometimes I see people literally replacing 80 caps or more without reason, when I have the same device sitting at home with its original caps, still doing its job well within spec for years.

dmix 4y ago

> Only later did I learn that it actually seemed to have been industrial espionage gone wrong! The relevant bit from Wikipedia: > Industrial espionage was implicated in the capacitor plague, in connection with the theft of an electrolyte formula. A materials scientist working for Rubycon in Japan left the company, taking the secret water-based electrolyte formula for Rubycon's ZA and ZL series capacitors, and began working for a Chinese company. The scientist then developed a copy of this electrolyte. Then, some staff members who defected from the Chinese company copied an incomplete version of the formula and began to market it to many of the aluminium electrolytic manufacturers in Taiwan, undercutting the prices of the Japanese manufacturers. This incomplete electrolyte lacked important proprietary ingredients which were essential to the long-term stability of the capacitors and was unstable when packaged in a finished aluminium capacitor. This faulty electrolyte allowed the unimpeded formation of hydroxide and produced hydrogen gas.

winReInstall 4y ago
Catalytic metals trace elements, that recombine those gases. Or else the hydrogen tunnels through all things, turning them brittle.. I sometimes wonder, how those secret sauces can remain so secret. After all, you have to order them in rather large batches every week, month, year..
- deleted 4y ago
  [deleted]

gymbeaux 4y ago

I think the main reason enthusiasts recap is to prevent damage to the rest of board when the capacitors swell and leak. E: I can't believe something so easy to Google is being downvoted as though it's false info: https://www.reddit.com/r/retrogaming/comments/ib7nyh/replacing_capacitors_from_retro_consoles/ https://www.reddit.com/r/retrogaming/comments/ib7nyh/replaci...