Power supplies with solid polymer caps
in [Repair]
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From: William Sommerwerck on 20 Nov 2009 09:38 >> If I interpret your question correctly, it's meaningless. >> Polymer capacitors (ie, plastic-dielectric caps, such as polystryrene, >> Mylar, and Teflon) simply cannot produce the huge capacitances in small >> spaces that electrolytics can. They cannot easily replace electrolytics. > I think the OP is referring to claims such as these: > http://event.asus.com/mb/5000hrs_VRM > *cough* *cough", indeed. 65 degrees C is 149 degrees F. I doubt that the average computer gets much past 100 degrees. I'm also curious as to how they can get so much capacitance in such a small space using plastic dielectrics. I've owned electronic equipment (that I bought myself) for 45 years. The /only/ piece of equipment that failed because of a bad electrolytic was a JVC hall synthesizer, which was manufactured with a run of bad caps. (I have two of these, and the second one also needs cap replacement, though I haven't gotten around to it.) It's true that electrolytics are among the least reliable of components -- but they're not /that/ unreliable.
From: stratus46 on 20 Nov 2009 11:30 On Nov 20, 6:38 am, "William Sommerwerck" <grizzledgee...(a)comcast.net> wrote: > >> If I interpret your question correctly, it's meaningless. > >> Polymer capacitors (ie, plastic-dielectric caps, such as polystryrene, > >> Mylar, and Teflon) simply cannot produce the huge capacitances in small > >> spaces that electrolytics can. They cannot easily replace electrolytics. > > I think the OP is referring to claims such as these: > >http://event.asus.com/mb/5000hrs_VRM > > *cough* > > *cough", indeed. > > 65 degrees C is 149 degrees F. I doubt that the average computer gets much > past 100 degrees. I'm also curious as to how they can get so much > capacitance in such a small space using plastic dielectrics. > > I've owned electronic equipment (that I bought myself) for 45 years. The > /only/ piece of equipment that failed because of a bad electrolytic was a > JVC hall synthesizer, which was manufactured with a run of bad caps. (I have > two of these, and the second one also needs cap replacement, though I > haven't gotten around to it.) > > It's true that electrolytics are among the least reliable of components -- > but they're not /that/ unreliable. Yeah they are. I've personally changed a couple thousand - 10x more than all other components combined - even mechanical wear out parts. G²
From: larry moe 'n curly on 20 Nov 2009 11:56 William Sommerwerck wrote: > > I've owned electronic equipment (that I bought myself) for 45 years. The > /only/ piece of equipment that failed because of a bad electrolytic was a > JVC hall synthesizer, which was manufactured with a run of bad caps. (I have > two of these, and the second one also needs cap replacement, though I > haven't gotten around to it.) > > It's true that electrolytics are among the least reliable of components -- > but they're not /that/ unreliable. Most of the stuff used now in retail products isn't anything close to the quality of the electrolytics by Spraque, Cornell-Dublier, Mallory, Nichicon, etc. Here's an analysis comparing the chemistry of some good Japanese caps to some bad Taiwanese ones: www.dfrsolutions.com/pdfs/2004_Electrolyte_Hillman-Helmold.pdf Here's a video card that wasn't much more than a year old when three of its caps (Sacon brand?) popped, and apparently they weren't exceptions from the norm: http://farm3.static.flickr.com/2350/2461471181_352c511a5a_o.jpg
From: Ken on 20 Nov 2009 13:24 On Thu, 19 Nov 2009 21:44:36 -0800, Daniel Prince <neutrino1(a)ca.rr.com> wrote: > I have read that electrolytic capacitors are the least reliable > component in power supplies. Very true.
From: Arfa Daily on 20 Nov 2009 20:30
"William Sommerwerck" <grizzledgeezer(a)comcast.net> wrote in message news:he69nj$d1d$1(a)news.eternal-september.org... >>> If I interpret your question correctly, it's meaningless. > >>> Polymer capacitors (ie, plastic-dielectric caps, such as polystryrene, >>> Mylar, and Teflon) simply cannot produce the huge capacitances in small >>> spaces that electrolytics can. They cannot easily replace electrolytics. > >> I think the OP is referring to claims such as these: >> http://event.asus.com/mb/5000hrs_VRM >> *cough* > > *cough", indeed. > > 65 degrees C is 149 degrees F. I doubt that the average computer gets much > past 100 degrees. I'm also curious as to how they can get so much > capacitance in such a small space using plastic dielectrics. > > I've owned electronic equipment (that I bought myself) for 45 years. The > /only/ piece of equipment that failed because of a bad electrolytic was a > JVC hall synthesizer, which was manufactured with a run of bad caps. (I > have > two of these, and the second one also needs cap replacement, though I > haven't gotten around to it.) > > It's true that electrolytics are among the least reliable of components -- > but they're not /that/ unreliable. > > Depending on how stressful the position that they are used in - and many such positions these days *are* - I would have to beg to differ. They really are /that/ unreliable ... Arfa |