On Thu, 22 Mar 2012 12:04:30 +0100, Attila Kinali <[email protected]> wrote:
>On Wed, 21 Mar 2012 22:33:49 -0700 >"John Miles" <[email protected]> wrote: > >> I did this for a while, but I eventually realized that new >> "computer grade" electrolytic capacitors no longer have the same >> quality levels that they must have had in the 1970s and 1980s. >> Back then, orders of magnitude more of them would have been used in >> production than are used today, and the manufacturers would have paid >> more attention to what they were doing. After my first few encounters >> with high-ESR parts out of the retail box, I stopped replacing good ones. > >That's not really true. More electrolytics are used today than were in the >70s and 80s, mostly because a lot more electronics is build today. >What is different though is that those electrolytics are more optimized >to be cheap than they were before. Which means that you have to more >carefully select the capacitor you are going to use. Main stuff you have >to look for is: ESR, maximum ripple current, operating temperature. >Especially the ripple current is important as this is what kills most >electrolytics in "cheap" or not well designed circuits these days. In the two Tektronix PS503As that I just rebuilt, out of 4 big aluminum can style input and 4 small axial style output electrolytic capacitors, the one of each set that went bad where marked "made in mexico" and had no identifiable manufacturer. The other 3 of each set were clearly marked Mallory for the large input ones and Sprague for the small output ones. In some old switching power supplies I fixed a couple of weeks ago, the axial Cornell Dubilier capacitors were in excellent shape while almost every other capacitor was worn out. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
