[sdiy] Reformatting Capacitors

[John L Marshall]

Scott,

I have reformed capacitors. Are they in good condition? Any evidence that
the electrolyte has leaked out? I have always used an adjustable power
supply. Crank the voltage up to maybe 25% and watch the current flow. When
the current drops close to zero crank the voltage up some more. Repeat until
the capacitors are up to operating voltage. If the current flow doesn't tend
towards zero then the capacitor has lost too much electrolyte. Too late. Too
bad.

I have some photo flash capacitors that are nearly 50 years old and are
still in good working condition.

John



----- Original Message -----
From: Scott Evans, Gen Mgr <esresource at earthlink.net>
To: DIY <synth-diy at dropmix.xs4all.nl>
Sent: Monday, February 18, 2002 6:29 PM
Subject: Re: [sdiy] Reformatting Capacitors


> Just an additional note, the gear is about 20 years old, just not "lit
> up" in the last nine.
>
> Thanks, Scott
>
> "Scott Evans, Gen Mgr" wrote:
> >
> > Hello all,
> >
> > I am going to be reworking some gear that has not been on in 9 years,
> > and want to try reformatting the electrolytic caps before going to
> > replacement. Couple of questions:
> >
> > 1. Is this a waste of time? Should I just go ahead and replace? I may
> > just do this for the inexpensive ones.
> >
> > 2. How high a voltage for a reformat? Full voltage, 50%?
> >
> > 3. How fast should take the caps to the reformatting voltage, i.e. 25%
> > steps for 10 Minutes?
> >
> > 4. After this process is finished, how can I test the caps to see if the
> > reformatting is successful? I have a Fluke with capacitance checking,
> > will this do?
> >
> > BTW, if there is a web page that describes the process, that would be
> > great.
> >
> > Thanks in advance to all who reply, I appreciated your help.
> >
> > Regards,
> >
> > Scott Evans
> >
> > "It is better to cherish virtue and humanity, leaving much to free
> > will ... than to attempt to make men machines and instruments of
> > political benevolence.  The world as a whole will gain by a liberty
> > without which virtue cannot exist."
> > Edmund Burke