View Single Post
  #53   Report Post  
Posted to sci.electronics.repair
whit3rd whit3rd is offline
external usenet poster
 
Posts: 2,017
Default Replacing Large Electrolytics

On Friday, August 24, 2018 at 10:35:43 PM UTC-7, Fox's Mercantile wrote:
On 8/24/18 6:42 PM, Cursitor Doom wrote:
I had 3 faulty electrolytics; all 30V/5500uF. In my spares bin I found 6
NOS (new old stock) electros ...
These spares, though unused, are probably 40 years old. Will they need re-
forming gradually over 24hrs before installing?


Reforming is a fool's game.
They either work to being with or they're bad.


That's not ny experience; yes, I might toss the 40--year-olds, but only
because new ones are cheap and probably better performing.
Even one-year-old capacitors can benefit from reforming, though,
and for some uses (timing capacitors) it's beneficial.

It doesn't take 24 hours, though: with a current-limited supply, just
give 'em 150% of the rated voltage and warm 'em with a hair
dryer for a few minutes, while watching the leakage current.
You can see it drop from milliamps to microamps.