Electrolytic cap voltage ratings

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CJ

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Those dry electrolytic are weird, just about every one I have checked has been in good working order. Even like caps from 1948, why this is I have no idea . probably because it is hard for something to dry out when it is already dry, except that wino on 4th street who is always begging for a short dog of port.

Some body bought some vitamin Q,s at an antique store, I informed them that some of them were hazardousness, the ones that sound best, but how can you enjoy music while knowing that a cancer bomb could explode at any moment,
 

Tubetec

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I have seen very long lasting electrolytics , as we know in terms of voltage and current being conservative does yeild extra life , stuff that was stored indoors like an old tube radio tends to fare out better than something thats been exposed to temperature extremes .
I bet that Dubilier Nitrogol 4uf PIO I used in the PSU has some nasty inside , PCB oil most likely , still nothing to worry about unless it develops a leak .
 

Tubetec

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Wow just googled 4th street in downtown LA ,that bridge and the river bed is well known from many films of course ,
instantly brought GSH to mind ,


In the course of renovating my HP 200CD gen I had to replace some of those big old lytic caps ,
One let its seals go and oozed out black viscous gunge , even after the power was off it still kept coming for a few minutes , definately worth wearing a pair of rubber gloves while handling these components if they have leaked .
As far as I know the PCB's (polychlorinated bisphenol) job was to prevent any thing microbial or fungus based from taking hold . Of course PCB based oils are no longer used in transformers , they have a modern transformer insulation oil now they call 'Michaelangelo A' without PCB additives .
 
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ccaudle

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a modern transformer insulation oil now they call 'Michaelangelo A'

The material sheet for Michaelangelo A shows a flash point of 152 deg. C. PCB oils were generally non flammable, and when they broke down under extremely high heat the vapors were non flammable. That was the primary advantage for transformers.
I think the dielectric properties were also favorable for capacitors, so I guess you would not want to use PCB oil for higher than power line frequency transformers. Moot point now since they were banned decades ago, but even the PBB replacements are banned in Europe under RoHS and in China under their equivalent. Not sure if North American countries have banned PBB yet, but probably anyone still making oil based capacitors or oil cooled transformers has to just use mineral oil based fluid now. Not sure how the flammability concerns are handled.

But unless you specifically want to use paper-in-oil for some kind of restoration of an antique to original condition, I don't think any of the oil concerns have relevance. Modern aluminum electrolytic caps use something completely different. In regards to Tubetec's reference to an old PIO cap, I'm not sure how to even find out what particular manufacturers used in old devices. Could be a concern for disposal if you are providing commercial repair/refurb services, or if you just care about proper disposal when doing your own work.
 

Tubetec

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Electronic and electrical waste here in Ireland is disposed of at civic amenity sites for free ,
I have marked things up as potentially hazardous on a few occassions when dealing with oil filled caps .

Theres plenty of other noxious chemicals waiting to get out of electronic gear , what about all these large Tv screens , led light bulbs and photovoltaic solar panels , old habbits die hard and lots of these will end up in landfill , all you can hear from the Green party is how great the low energy gear is for the environment and have they even considdered impact of this stuff over the longer term when it leaches out into rivers and streams , no they havent . The information on whats safe to dump isnt easy to find and in the absence of knowledge people will default back to the old way .
I worked in a tv and hifi repair place years ago , all the old CRT tubes from TV's and monitors had to have the vaccum broken and then get shipped to Germany for re-processing ,was very costly .
 
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