Ok that leads to a question.
how often (x times per y years) should old equipment be powered on to safegaurd them?
drives, systems, etc?
How about turning on a hard drive and doing a read of the whole disk just to revive the
magnetic flux?
boot your vax once every x years just to get it going
same for c64s, etc
Date: Tue, 28 Jan 2014 17:47:11 -0700
Subject: RE: 1541 Alignment disk
From: spacewar at
gmail.com
To: cctalk at
classiccmp.org
On Jan 28, 2014 5:17 PM, "Peter Coghlan" <cctech at beyondthepale.ie>
wrote:
Electrolytic capacitors can leak or explode but
in my experience they
don't
do it very often. Like anything else, they can
be incorrectly specified
or
a bad batch can cause problems.
Aside from the infamous incomplete-stolen-formula problem, I've only seen
them leak or explode when overstressed. Note that the closer to the maximum
rating you operate them, the shorter their life will be.
On the other hand, if you leave them unused for many years, the oxide layer
breaks down. It's a gradual process, and the effective maximum voltage they
can handle goes down. If you try to use them at the original rated voltage,
or anywhere above whatever max voltage they've deteriorated to, they will
be irreversibly damaged, which may or may not cause a seal rupture or other
visible (or audible) effects.
Applying a current-limited power supply to them can "reform" them, by
growing back the oxide layer in roughly the same way it was done when the
capacitor was originally manufactured.
On the PDP-1 restoration project, because we had a very strong bias against
replacing components unnecessarily, we used an incredibly overengineered
process to test the electrolytic capacitors and reform those that needed
it. For artifacts substantially more commonplace than the PDP-1, I'd
exercise care, but not to the extreme we went to on that project.