Surplus caps how old is too old? - diyAudio
Go Back   Home > Forums > General Interest > Everything Else

Everything Else Anything related to audio / video / electronics etc) BUT remember- we have many new forums where your thread may now fit! .... Parts, Equipment & Tools, Construction Tips, Software Tools......

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 6th June 2002, 03:25 PM   #1
diyAudio Member
 
Join Date: Jan 2002
Location: Tyrone Ga. U.S.A.
Default Surplus caps how old is too old?

In cleaning out my garrage I found a box of electrolitic caps I had
bought back in 1980. They seem to still be healthy but is there any way to predict how long an old cap like this will last if put to
use. When charged up to their rated voltage these 15,000uf 63v
Marcom caps didn't seem to have any leakage current to speak of
and held a charge for a few hours when disconnected. I have 20 of these I would like to find a new home for but don't want to sell
anything that is likely to fail real soon.

Thanks for past and future help,


Woody AKA bob12345678
  Reply With Quote
Old 6th June 2002, 04:51 PM   #2
tiroth is offline tiroth  United States
diyAudio Member
 
Join Date: Dec 2001
Location: Pittsburgh, PA, USA
You could test the ESR. I believe a major failure mechanism is aging causes a rise in ESR, which causes higher dissipation, faster aging, etc.
  Reply With Quote
Old 6th June 2002, 04:57 PM   #3
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
I like surpluss caps too. Check my other thread dealing with that matter: How long electrolytic caps last?
  Reply With Quote
Old 17th June 2002, 11:58 AM   #4
yeti is offline yeti  Germany
diyAudio Member
 
Join Date: Nov 2001
Location: Ewersbach
Default old caps

Usually they should still be ok,but possibly the dielctric must be reformed.
To do so ,you can connect a variable power supply to the caps in series with an ammeter, now increase the voltage to 1/3 of the maximum voltage of the caps.
At the beginnig there will be a certain amount of leakage current that decreases after a while, if the leakage current is below 1 mA you can slowly increase the voltage applied.
If you reached Vmax * 1.2 at a reasonable leakage current the caps should do for te next 10 years.

regards; Arne
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
NYC Surplus??? imix500 Everything Else 2 28th June 2006 10:06 PM
surplus 12ax7a jaudio Tubes / Valves 0 31st December 2004 11:28 PM
found some cheap surplus caps (big but low voltage) cowanrg Parts 0 3rd December 2004 06:53 AM
Source for surplus PCB jmateus Parts 10 8th July 2003 12:18 PM


New To Site? Need Help?

All times are GMT. The time now is 05:58 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2