Help! electrolytic capacitor 5000 MFD needed

Looking for a replacement for a blown Mallory electrolytic capacitor for a
power supply. The capacitor has three terminals, 2 red and one black. The
capacitor label has the following notation:

Mallory
5000 MFD 20 VDC RED
5000 MFD 20 VDC RED
25002 235-7244A

I did a Google search and could not find anything similar. I am wondering
if anyone has any idea where I could find a suitable replacement.

The capacitor is part of an EICO Battery ELiminator and Charger, Model
1064S.

Any assistance would be greatly appreciated.

On Sun, 5 Mar 2006 17:11:37 -0600, "DB" <DLB613_at_charter.net> wrote:



Looking for a replacement for a blown Mallory electrolytic capacitor for a
power supply. The capacitor has three terminals, 2 red and one black.
The
capacitor label has the following notation:

Mallory
5000 MFD 20 VDC RED
5000 MFD 20 VDC RED
25002 235-7244A

I did a Google search and could not find anything similar. I am wondering
if anyone has any idea where I could find a suitable replacement.

The capacitor is part of an EICO Battery ELiminator and Charger, Model
1064S.

Any assistance would be greatly appreciated.

---
Unless you need an exact replacement for esthetic reasons, any
modern aluminum electrolytic capacitor rated for 20V or more should
work.

If the capacitors are used singly you'll need to get something like
two, 5100µF 20V caps or of they're wired in parallel, a single
10000µF 20V cap should work. Check Digi-Key or Mouser, they're sure
to have something you can use.

Do you have a schematic you can post?

--
John Fields
Professional Circuit Designer

Unfortunately I don't have a schematic. There is only one capacitor, but it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?

- D. Boucher

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:a6um029tsjuea93tqsj00vl7ou60qkhnej_at_4ax.com...
On Sun, 5 Mar 2006 17:11:37 -0600, "DB" <DLB613_at_charter.net> wrote:


Looking for a replacement for a blown Mallory electrolytic capacitor for a
power supply. The capacitor has three terminals, 2 red and one black.
The
capacitor label has the following notation:

Mallory
5000 MFD 20 VDC RED
5000 MFD 20 VDC RED
25002 235-7244A

I did a Google search and could not find anything similar. I am wondering
if anyone has any idea where I could find a suitable replacement.

The capacitor is part of an EICO Battery ELiminator and Charger, Model
1064S.

Any assistance would be greatly appreciated.
---
Unless you need an exact replacement for esthetic reasons, any
modern aluminum electrolytic capacitor rated for 20V or more should
work.

If the capacitors are used singly you'll need to get something like
two, 5100µF 20V caps or of they're wired in parallel, a single
10000µF 20V cap should work. Check Digi-Key or Mouser, they're sure
to have something you can use.

Do you have a schematic you can post?

--
John Fields
Professional Circuit Designer

DB wrote:
Unfortunately I don't have a schematic. There is only one capacitor, but it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?

- D. Boucher

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:a6um029tsjuea93tqsj00vl7ou60qkhnej_at_4ax.com...
On Sun, 5 Mar 2006 17:11:37 -0600, "DB" <DLB613_at_charter.net> wrote:


Looking for a replacement for a blown Mallory electrolytic capacitor for
a
power supply. The capacitor has three terminals, 2 red and one black.
The
capacitor label has the following notation:

Mallory
5000 MFD 20 VDC RED
5000 MFD 20 VDC RED
25002 235-7244A

I did a Google search and could not find anything similar. I am
wondering
if anyone has any idea where I could find a suitable replacement.

The capacitor is part of an EICO Battery ELiminator and Charger, Model
1064S.

Any assistance would be greatly appreciated.
---
Unless you need an exact replacement for esthetic reasons, any
modern aluminum electrolytic capacitor rated for 20V or more should
work.

If the capacitors are used singly you'll need to get something like
two, 5100µF 20V caps or of they're wired in parallel, a single
10000µF 20V cap should work. Check Digi-Key or Mouser, they're sure
to have something you can use.

Do you have a schematic you can post?

--
John Fields
Professional Circuit Designer



Two capacitors, that share a single negative terminal, in the one
package. Cannot say I've seen it before but sounds reasonable.

Failing a schematic, can you try following the actual circuit to give us
an idea?

Is it possible that the wires off the capacitor red leads go to the
cathodes of two diodes who's anode then connect to windings on a
transformer with the capacitors negative terminal going to another
transformer terminal?

Daniel
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Unfortunately I don't have a schematic. There is only one capacitor, but it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?

On Sun, 5 Mar 2006 22:49:35 -0600, "DB" <DLB613_at_charter.net> wrote:

Unfortunately I don't have a schematic. There is only one capacitor,
but it
has three terminals. That and the notation on the side makes me
think it
may be some kind of a dual capacitor in one big can. I had never
heard of
such a thing before, but could that be what it is?

---
Please bottom post.

More than likely, that's precisely what it is. Back in the stony
ages it was quite common to have two or three electrolytics in the
same can. The way you describe yours though, makes it sound like
there's a separate terminal coming out of the base for the common
connection, when usually a tab which was part of the case was used
for the common connection. Is thare any other marking on the case?
Like "TYPE FP" or anything like that?

The reason I ask is because there are lots of people selling Mallory
capacitors on the web, and if you know the type number you should be
able to use Goggle to find a source.

Failing that, If you took the thing apart to find out what's
_really_ in the can, as Al suggested, you could substitute what's in
there with new caps or, if you wanted to get really fancy, put the
new caps in the old can for a tidy repair. Caps today are so much
smaller than they were back then they'd prob'ly fit right in there.

--
John Fields
Professional Circuit Designer

On Sun, 5 Mar 2006 22:49:35 -0600, "DB" <DLB613_at_charter.net> wrote:

Unfortunately I don't have a schematic. There is only one capacitor, but
it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?

---
Please bottom post.

More than likely, that's precisely what it is. Back in the stony
ages it was quite common to have two or three electrolytics in the
same can. The way you describe yours though, makes it sound like
there's a separate terminal coming out of the base for the common
connection, when usually a tab which was part of the case was used
for the common connection. Is thare any other marking on the case?
Like "TYPE FP" or anything like that?

The reason I ask is because there are lots of people selling Mallory
capacitors on the web, and if you know the type number you should be
able to use Goggle to find a source.

Failing that, If you took the thing apart to find out what's
_really_ in the can, as Al suggested, you could substitute what's in
there with new caps or, if you wanted to get really fancy, put the
new caps in the old can for a tidy repair. Caps today are so much
smaller than they were back then they'd prob'ly fit right in there.

--
John Fields
Professional Circuit Designer

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:0aoo02lehaq7hgejn4vo6n1sp5t2oasvka_at_4ax.com...
On Sun, 5 Mar 2006 22:49:35 -0600, "DB" <DLB613_at_charter.net> wrote:

Unfortunately I don't have a schematic. There is only one capacitor, but
it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?

---
Please bottom post.

More than likely, that's precisely what it is. Back in the stony
ages it was quite common to have two or three electrolytics in the
same can. The way you describe yours though, makes it sound like
there's a separate terminal coming out of the base for the common
connection, when usually a tab which was part of the case was used
for the common connection. Is thare any other marking on the case?
Like "TYPE FP" or anything like that?

The reason I ask is because there are lots of people selling Mallory
capacitors on the web, and if you know the type number you should be
able to use Goggle to find a source.

Failing that, If you took the thing apart to find out what's
_really_ in the can, as Al suggested, you could substitute what's in
there with new caps or, if you wanted to get really fancy, put the
new caps in the old can for a tidy repair. Caps today are so much
smaller than they were back then they'd prob'ly fit right in there.

--
John Fields
Professional Circuit Designer

I opened the power supply up and traced the wires. The black terminal is
connected directly to the negative output terminal. One of the red
terminals is connected directly to the positive output terminal. The other
red terminal is also connected to the positive output, but through a large
coil with an iron core. The second red terminal is also connected to a DPDT
switch that selects the output range and through that to a diode array and a
variable transformer.

There are no markings on the capacitor other than what I indicated in my
first post.

I'll try the thing of putting new caps in the old can -- it would certainly
make it easier to mount them.

- DB

Looks like what you have is a pi filter. Leading cap., choke, trailing
cap. Values of the caps are important in this schema.

Al

Looks like what you have is a pi filter. Leading cap., choke, trailing
cap. Values of the caps are important in this schema.

Al

db, are you for sure that the caps are bad?
What was the problem that lead you to diagnose the caps?

leaking or exploded? I have changed caps before , but its not that
often a main power supply filter dies. Tell us what the unit was doing...

On Sun, 5 Mar 2006 22:49:35 -0600, "DB" <DLB613_at_charter.net> wrote:

Unfortunately I don't have a schematic. There is only one capacitor, but
it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?


More than likely, that's precisely what it is. Back in the stony
ages it was quite common to have two or three electrolytics in the
same can. The way you describe yours though, makes it sound like
there's a separate terminal coming out of the base for the common
connection, when usually a tab which was part of the case was used
for the common connection. Is thare any other marking on the case?
Like "TYPE FP" or anything like that?

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:0aoo02lehaq7hgejn4vo6n1sp5t2oasvka_at_4ax.com...
On Sun, 5 Mar 2006 22:49:35 -0600, "DB" <DLB613_at_charter.net> wrote:

Unfortunately I don't have a schematic. There is only one capacitor, but
it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?


More than likely, that's precisely what it is. Back in the stony
ages it was quite common to have two or three electrolytics in the
same can. The way you describe yours though, makes it sound like
there's a separate terminal coming out of the base for the common
connection, when usually a tab which was part of the case was used
for the common connection. Is thare any other marking on the case?
Like "TYPE FP" or anything like that?

I picked up a couple of 5000 MFD 25VDC capacitors for $1 each, hoping that
they might be suitable replacements. The new capacitors are marked "Type
PFP." The old 5000 MFD 20VDC dual capacitor didn't have any markings to
indicate the type. The old capacitor case looks like it is made of
bakelite, by the way.

The new capacitors have three terminals that are part of the aluminum case,
and a fourth terminal slightly off-center from the base. The fourth
terminal has a little square marking next to it. There does not appear to
be any measureable resistance between any of the terminals, including the
central one.

I am wondering how I can determine if these capacitors are suitable
replacements. I'm also not sure how to figure out which terminal should be
connected to the positive output of the power supply, and which to the
negative. Any assistance would be greatly appreciated.

"James Thompson" <jtech7_at_alltel.net> wrote in message
news:eec4c$441276e5$438c80c6$12279_at_ALLTEL.NET...
Looks like what you have is a pi filter. Leading cap., choke, trailing
cap. Values of the caps are important in this schema.

Al
db, are you for sure that the caps are bad?
What was the problem that lead you to diagnose the caps?

leaking or exploded? I have changed caps before , but its not that
often a main power supply filter dies. Tell us what the unit was doing...


One minute the Power supply was working fine, then it vibrated for a split
second and then the fuse blew. I replaced the fuse, and the same thing
happened again when I turned it on. I opened the power supply up and I saw
that there was some dried yellow crusty material that appeared to have oozed
out of the capacitor near one of the terminals. It looked like it had been
that way for a while, but I had just recently started using this power
supply after it had been sitting on a shelf for about 12 years.

I checked the resistance between the capacitor terminals (without removing
the capacitor from the circuit), and found that there was no resistance. I
don't know if that is normal.

- D. Boucher

On Sat, 11 Mar 2006 14:36:05 -0600, "DB" <DLB613_at_charter.net> wrote:

"John Fields" <jfields_at_austininstruments.com> wrote in message
news:0aoo02lehaq7hgejn4vo6n1sp5t2oasvka_at_4ax.com...
On Sun, 5 Mar 2006 22:49:35 -0600, "DB" <DLB613_at_charter.net> wrote:

Unfortunately I don't have a schematic. There is only one capacitor, but
it
has three terminals. That and the notation on the side makes me think it
may be some kind of a dual capacitor in one big can. I had never heard of
such a thing before, but could that be what it is?

More than likely, that's precisely what it is. Back in the stony
ages it was quite common to have two or three electrolytics in the
same can. The way you describe yours though, makes it sound like
there's a separate terminal coming out of the base for the common
connection, when usually a tab which was part of the case was used
for the common connection. Is thare any other marking on the case?
Like "TYPE FP" or anything like that?
I picked up a couple of 5000 MFD 25VDC capacitors for $1 each, hoping that
they might be suitable replacements. The new capacitors are marked "Type
PFP." The old 5000 MFD 20VDC dual capacitor didn't have any markings to
indicate the type. The old capacitor case looks like it is made of
bakelite, by the way.

The new capacitors have three terminals that are part of the aluminum case,
and a fourth terminal slightly off-center from the base. The fourth
terminal has a little square marking next to it. There does not appear to
be any measureable resistance between any of the terminals, including the
central one.

I am wondering how I can determine if these capacitors are suitable
replacements. I'm also not sure how to figure out which terminal should be
connected to the positive output of the power supply, and which to the
negative. Any assistance would be greatly appreciated.

---
The capacitor you have is one of the Mallory PFP types which is a
twist-lock capacitor for PCB mounting. Twist-lock because usually
the tabs on the case were slipped through slots in the PCB (type
PFP) or through the chassis (type FP), and then the tabs were
twisted with a pair of pliers to lock the capacitor down.

The case is almost certainly negative, leaving the center pin
positive.

The reason you're measuring zero resistance between the center pin
and the case is because they're pretty good size capacitors and
it'll take a good while for them to charge up with the current from
your ohmmeter.

oxide on the plates might not be in the best condition, so what you
might want to do is put an ammeter in series with the cap and
measure the current going into it while it's charging from a low
voltage. When you first connect it the ammmeter will show a _LOT_
of current, but as time goes by you should see the current drop and
eventually settle on a very low value. When it gets stable,
increase the voltage and watch the current until it gets stable
again. Do that until the voltage across the capacitor is at 25V,
and then just let it sit there with power on it for a few hours. If
everything is OK the ammeter should read only a few milliamperes
after a few hours.

BTW, what kind of test equipment do you have access to?

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