Reforming capacitors?

AndrewT · 5th January 2006, 07:19 AM

Hi,
I am reforming capacitors for the smoothing banks of a variety of amps. Most are new old stock 2 to 3 year old. Some are much older and been out of use for 8 years.

Can I reform upto working voltage with a 1M2 series resistor without any risk?

Can I use a higher charging voltage and take the caps off charge when they reach working voltage?
Is there a risk of not reforming properly if the charge period is shortened to less than 24hrs or 12hrs?

Can I reform, slowly, to higher than working voltage, IF the reforming current stays low?
I'm thinking working voltage +10% through 1M2 resistor.

lineup · 5th January 2006, 07:25 AM

I didnt know you can reform caps.

I found this article
Steven W. Moore - Reforming Capacitors

At bottom of his page are two reference links, about same subject.

more links:
http://ed-thelen.org/1401Project/Tri...apacitors.html
http://www.chemi-con.com/u7002/toc.php
http://www.vmars.org.uk/capacitor_reforming.htm
http://www.angelfire.com/electronic/...store_cap.html

.... and from USA

DEPARTMENT OF DEFENSE
HANDBOOK FOR
STORAGE SHELF LIFE AND
REFORMING PROCEDURES FOR
ALUMINUM ELECTROLYTIC FIXED CAPACITORS
http://www.dscc.dla.mil/Programs/Mil...=MIL-HDBK-1131

woody · 23rd March 2008, 05:21 PM

I see we have a lot of threads on reforming caps but I
have another question. Can you reform a bipolar cap?

5th January 2006, 07:19 AM	#1
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Reforming capacitors? Hi, I am reforming capacitors for the smoothing banks of a variety of amps. Most are new old stock 2 to 3 year old. Some are much older and been out of use for 8 years. Can I reform upto working voltage with a 1M2 series resistor without any risk? Can I use a higher charging voltage and take the caps off charge when they reach working voltage? Is there a risk of not reforming properly if the charge period is shortened to less than 24hrs or 12hrs? Can I reform, slowly, to higher than working voltage, IF the reforming current stays low? I'm thinking working voltage +10% through 1M2 resistor.

5th January 2006, 07:25 AM	#2
lineup diyAudio Member Join Date: Dec 2005 Location: the north	I didnt know you can reform caps. I found this article Steven W. Moore - Reforming Capacitors At bottom of his page are two reference links, about same subject. more links: http://ed-thelen.org/1401Project/Tri...apacitors.html http://www.chemi-con.com/u7002/toc.php http://www.vmars.org.uk/capacitor_reforming.htm http://www.angelfire.com/electronic/...store_cap.html .... and from USA DEPARTMENT OF DEFENSE HANDBOOK FOR STORAGE SHELF LIFE AND REFORMING PROCEDURES FOR ALUMINUM ELECTROLYTIC FIXED CAPACITORS http://www.dscc.dla.mil/Programs/Mil...=MIL-HDBK-1131 __________________ lineup

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23rd March 2008, 05:21 PM	#3
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	I see we have a lot of threads on reforming caps but I have another question. Can you reform a bipolar cap?