PDP 11 gear finally moved
tothwolf at concentric.net
Sun Jul 19 20:53:43 CDT 2015
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
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).
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