1541 Alignment disk

On Jan 28, 2014 5:17 PM, "Peter Coghlan" <cctech at beyondthepale.ie> wrote: don't or 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.