Well, all I can say is that my experience differs. I have had newer capacitors fail, and old ones, too, of course, but nothing points to wholesale replacement as a cost or time effective strategy, especially on something like an Altair. FWIW, I don't run my vintage machines all that often. Of course reforming a bad capacitor, whatever the failure mode, is going to be useless.
Tothwolf <tothw...@concentric.net> wrote: >On Fri, 17 Jul 2015, Jay Jaeger wrote: >> On 7/17/2015 1:33 PM, Rich Alderson wrote: >> >>>> It is generally a good idea to re-form electrolytic capacitors in >>>> power supplies, and to bench check the power supplies (under some kind >>>> of load) before actually applying power to the whole unit. >>> >>> It is always a good idea to replace electrolytic capacitors in power >>> supplies. The rest of the advice is sound. >>> >> Replace - no, I don't agree - especially not for those of us who don't >> have the kind of budget that your organization has. In my experience, >> for equipment of this quality and vintage, 95% or more of the time an >> hour to a few hours of re-forming is all that is necessary - and as Tony >> has pointed out, even that is not often really necessary. > >Replace - yes, *especially* if you don't have a big budget. Aluminum >electrolytic capacitors are CHEAP and easy to obtain. Replacement >semiconductors by comparison are expensive and can be quite difficult to >find. > >While it might be worthwhile reforming a special purpose NOS electrolytic >that isn't much older than 15-20 years old, reforming 20-30 year old >heavily used (read: past usable service life; evaporation of the >electrolyte, corrosion of the foils and especially foil to terminal >junctions, etc) is a complete and total waste of time. > >Ironically, 20-30 years ago this same mindset used to persist with people >who collected vacuum tube (valve) based radios and television, however >that attitude no longer seems to be present in those communities today >(not worth risking an irreplaceable transformer or inductor over >$5.00-$10.00 worth of aluminum electrolytics).