CAPACITOR QUESTION

[Dennis Bush]

If my question seems stupid it is because I am new to this and trying my
best to learn how to make repairs to some basic boards. OK Here goes:

I had to replace two barrel type capacitors on a control board for a pinball
machine. The capacitors were marked 470mfd35v and I replaced them with
nichion 470uf35v. I read that you had to reform capacitors when replacing
them. It that true for brand new capacitors or just used ones. Please email
bushden@tcnj.edu

Thanks for your help
Dennis

 

[default]

Modern caps don't require reforming after a prolonged period of
storage in a discharged state. Don't sweat it (unless you have some
truly old caps and plan to work them close to their maximum voltage
rating).

On Thu, 31 Jul 2003 13:00:04 GMT, "Dennis Bush" <bushden@tcnj.edu>
wrote:

If my question seems stupid it is because I am new to this and trying my
best to learn how to make repairs to some basic boards. OK Here goes:

I had to replace two barrel type capacitors on a control board for a pinball
machine. The capacitors were marked 470mfd35v and I replaced them with
nichion 470uf35v. I read that you had to reform capacitors when replacing
them. It that true for brand new capacitors or just used ones. Please email
bushden@tcnj.edu

Thanks for your help
Dennis

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[miketinte]

One is 470 microfarads will the other is 470 MILLIfarads... that's a
huge difference....you might want to check that...I know that doesn't
answer your original question

"Dennis Bush" <bushden@tcnj.edu> wrote in message news:<c628c8502bad5ea3edfbab3511aeed4b@free.teranews.com>...

If my question seems stupid it is because I am new to this and trying my
best to learn how to make repairs to some basic boards. OK Here goes:

I had to replace two barrel type capacitors on a control board for a pinball
machine. The capacitors were marked 470mfd35v and I replaced them with
nichion 470uf35v. I read that you had to reform capacitors when replacing
them. It that true for brand new capacitors or just used ones. Please email
bushden@tcnj.edu

Thanks for your help
Dennis

 

[default]

mfd and ufd are both read as Microfarad not "milli" Mfd is the older
designation.

On 31 Jul 2003 10:12:04 -0700, mlt3@lehigh.edu (miketinte) wrote:

One is 470 microfarads will the other is 470 MILLIfarads... that's a
huge difference....you might want to check that...I know that doesn't
answer your original question

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[Wouter van Ooijen (www.vo]

One is 470 microfarads will the other is 470 MILLIfarads...

I doubt that. The m is often misused to indicate micro. And a 470
millifarad cap would be huge!


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

 

[default]

On Thu, 31 Jul 2003 22:04:10 -0400, "Robert Morein"
<nowhere@nothing.com> wrote:

That's news to me.
I recently looked at a manufacturer's website.
After two years, specs are not met without reforming.

Interesting. Prompted me to take out several of my stock of

electrolytics. 100uf to 1000 uf range. I measured capacity and all
were over the marked value, some by 200%. Applied the rated working
voltage in one go from a brute force PS (no regulator and level set by
the input variac). Applied voltage and charged them and no problems.
Left several of the same voltage on for hours with no failures.

Gave a few a harsher test by shorting the cap and supply. That gives
a spike of ~20% higher with my lash-up when the voltage returns.

Maybe the makers are covering their ass with the specs? Or perhaps
they meet some ambient temperature or ripple current spec while
testing.

Some of my caps are over 20 years old. The oldest did have lower
capacity versus fresh ones, but they were still over the rated values
but no 200% ones.

Which website? I'd be curious to see which specs they mean. Tantelum
electrolytics may be a different case, Ive seen those fail, but no
aluminum electrolytics.


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[DarkMatter]

On 31 Jul 2003 10:12:04 -0700, mlt3@lehigh.edu (miketinte) Gave us:

One is 470 microfarads will the other is 470 MILLIfarads... that's a
huge difference....you might want to check that...I know that doesn't
answer your original question

It would also be over ten times bigger physically. DOH!

 

[Dennis Bush]

Wow you folks really have me confused now. The original board and capacitor
was made in early 1970 and are clearly marked nichion 470mfd35v. Now I went
to several electronic suppliers and cannot find a 470mfd35v(millifarad) in
a aluminum axial type capacitor which make me wonder now is it a microfarad
marked mfd according to older standards or not. Man am I confused.

Dennis
"Wouter van Ooijen (www.voti.nl)" <wouter@voti.nl> wrote in message
news:3f29777e.121705002@news.xs4all.nl...

One is 470 microfarads will the other is 470 MILLIfarads...

I doubt that. The m is often misused to indicate micro. And a 470
millifarad cap would be huge!


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

 

[DarkMatter]

On Fri, 01 Aug 2003 16:03:26 GMT, "Dennis Bush" <bushden@tcnj.edu>
Gave us:

Wow you folks really have me confused now. The original board and capacitor
was made in early 1970 and are clearly marked nichion 470mfd35v. Now I went
to several electronic suppliers and cannot find a 470mfd35v(millifarad) in
a aluminum axial type capacitor which make me wonder now is it a microfarad
marked mfd according to older standards or not. Man am I confused.

A 470uF at 35 volts is not that big a cap. Maybe 3/4" by 2" max.
Low ESR models would be slightly larger.

A 470 mF cap, on the other hand, is HUGE, not leaded at all
(terminals), and likely not around anymore at all, except in surplus
stores or military surplus.

I can say with near total certainty that it is a 470 microfarads as
you are not feeding a 20 amp circuit with the damned thing.
%99.9999 certain.

 

[Lee]

No need for confusion, was the replacement caps 1000 times the
physical size of the originals or not? There in lies your clue.
mfd has always meant microfarad as has uf, don't let the doofus
scare you so easy. If you want to talk millifarad you do it like
this - 470,000,000uf. So it still comes down to microfarads.

"Dennis Bush" <bushden@tcnj.edu> wrote in message news:<07fbfba7259e45ef2e4b27ba4aa338b1@free.teranews.com>...

Wow you folks really have me confused now. The original board and capacitor
was made in early 1970 and are clearly marked nichion 470mfd35v. Now I went
to several electronic suppliers and cannot find a 470mfd35v(millifarad) in
a aluminum axial type capacitor which make me wonder now is it a microfarad
marked mfd according to older standards or not. Man am I confused.

Dennis
"Wouter van Ooijen (www.voti.nl)" <wouter@voti.nl> wrote in message
news:3f29777e.121705002@news.xs4all.nl...
One is 470 microfarads will the other is 470 MILLIfarads...

I doubt that. The m is often misused to indicate micro. And a 470
millifarad cap would be huge!


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

 

[Stepan Novotill]

No manufacturer has EVER labelled a cap in millifarads.
m is the antiquated designation for mico.

....I know !

On Fri, 01 Aug 2003 07:29:02 -0700, DarkMatter
<DarkMatter@thebarattheendoftheuniverse.org> wrote:

On 31 Jul 2003 10:12:04 -0700, mlt3@lehigh.edu (miketinte) Gave us:

One is 470 microfarads will the other is 470 MILLIfarads... that's a
huge difference....you might want to check that...I know that doesn't
answer your original question


It would also be over ten times bigger physically. DOH!

 

[Overlord]

I take it that the ufd is actually ľfd then?
Haven't been in this for a while now and I still look for mmfd on
caps.
(hope the news readers don't kill my old DOS keypad stuff....)

On Thu, 31 Jul 2003 16:03:18 -0400, default <R75/5@defaulter.net>
wrote:

mfd and ufd are both read as Microfarad not "milli" Mfd is the older
designation.

On 31 Jul 2003 10:12:04 -0700, mlt3@lehigh.edu (miketinte) wrote:

One is 470 microfarads will the other is 470 MILLIfarads... that's a
huge difference....you might want to check that...I know that doesn't
answer your original question
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