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Old 6th July 2008, 06:40 PM   #1
atmars is offline atmars  United States
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Default Need help - Old cap can ID

I have some old cap cans that I need to replace. I have looked on this forum and the web but I can't seem to find a definitive answer, so I am wondering if anyone here knows about this type. I know the values but I am not sure how to identify the connection posts. All appear to be single caps, not multiple caps in the same can. Having said that, all have four connection points. One in the center and three at the perimeter. The perimeter pins are used for mounting and I am assuming the extras as extra solder points. However nothing is marked. The wiring layout is confusing enough that I would like to hear some opinions before I start disconnecting stuff. Is there a wiring scheme for these as far as +/- ? Are the three outer pins identical or is one the contact point and the rest superfluous? How can one tell? Is the center pin the + or the - connection?

Tried to attach a photo.

http://s294.photobucket.com/albums/m...t=P7060006.jpg

If you look close you can see the electrolyte oozing out.
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Old 6th July 2008, 08:00 PM   #2
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Most likely the connections are all the same if its a single value. With multiple values they usually use shapes to identify the tabs. Like a triangle or half circle. Double check with an ohm meter to be sure.
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Old 7th July 2008, 12:21 AM   #3
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The three outer tabs - also used for mounting - are connected together, to the outer shell of the cap, which is the negative terminal. The inner tab is the positive side.

They often connected to whichever tab(s) made wiring easier. You can connect them however you like.

Pete
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Old 7th July 2008, 12:37 AM   #4
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The three connections around the the center terminal are all common and are the negative side of the capacitor. They all connect to the outside of the capacitor and also serve as mounting tabs. You may use any or all of them for the negative terminal(s). The center is the positive terminal.

I noticed in the picture that there are several of what's come to be known as 'bumble-bee" capacitors. These are the ones with a black plastic body with colored stripes around them. This tells me that this item is from the 50's or early 60's at the latest. These capacitors, which are paper-in-oil types, are known to become leaky with age and should be checked and replaced as needed.

The bizarre thing is that I've seen people pay phenomenal money on fee-bay for these old used garbage capacitors. And I mean well over $100 for just one or two pieces. I think they were used in the old Gibson guitars like the Les Paul's etc. And even though there is no leakage problems from high voltage there, it still blows my mind that anyone would pay that much. And yea-yea, I know originality has it's price.

Victor
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Old 7th July 2008, 02:39 PM   #5
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Quote:
Originally posted by HollowState
I noticed in the picture that there are several of what's come to be known as 'bumble-bee" capacitors. These are the ones with a black plastic body with colored stripes around them. This tells me that this item is from the 50's or early 60's at the latest. These capacitors, which are paper-in-oil types, are known to become leaky with age and should be checked and replaced as needed.
I don't believe they all are oil-filled, they are used in Citation II and other Citation gear. When I cut open a few I found no evidence of oil impregnation.

Look on this page for a great pictorial on how to tell PIO from Mylar 'bees:

http://doctorvintage.com/electrics/gib_electricals.html
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Old 7th July 2008, 04:03 PM   #6
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Quote:
Originally posted by Jim McShane


Look on this page for a great pictorial on how to tell PIO from Mylar 'bees:

http://doctorvintage.com/electrics/gib_electricals.html
That's an interesting site that I've not seen before. Thanks for the heads up. It's a little difficult to tell from atmars's picture which type he has.

Victor
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