Electronics > Repair

[solved]Replacement capacitor, same brand & value, but 3 leads??

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Gen-8bit:
Hello from the PNW, I really need some help here;
I'm in the process of fixing my Zenith ZF-171 luggatop. I need to replace both Malleroy 780μf, 75 Vdc capacitors on the power supply board, which seem to be extremely difficult to find. The only ones I came across were found on this eBay auction: #https://www.ebay.com/itm/193860551121&ved=2ahUKEwj11vvmgoOKAxVFDzQIHQsXGa0Qjjh6BAgbEAE&usg=AOvVaw3gEAgal-_sXAVrvEYSI507.

As these at the time seemed the only ones I could find, and I was a bit impatient, I didn't pay attention to the fact they had a third lead attached on the top and down the side of the capacitor.

Well, I'm now stuck with those and need to make them work somehow, so here is the prize question: What is the extra lead wire for and how can I plug it on the board in place of the normal two lead ones? I did some research but that didn't help much. Some say it's for physical support, others say it's the negative lead and two positive leads, then again it's allegedly two caps in one. What is it now? 

If the top lead is negative, can't I just clip off one of the two bottom leads and fit it like a standard "two legged" capacitor?

Haenk:
Other than for looks, I would not use this decades old capacitor, at all.
If you don't care about the looks just replace with a modern capacitor, like 1000uF 100V (might want to go to a even higher voltage). Use a part from a well known company (Nichicon, Chemicon and so on.), you might want to show us the PCB where it goes in, but I assume anything will work. A "standard" part might be better seuited than a "low ESR for switching power supplies" model.
If you want to keep the vintage look, hollow out the old cap and hotglue the new one into it. (Careful not to short out anything etc. pp.)

coromonadalix:
same answer as previous

some open the cans to put more recent ones in them  just to keep the look intact ...

my friend rebuild lamp radios and do this trick

Gen-8bit:
As mentioned before, I'm stuck with a 10pack of these and they were the only ones with the exact values, so I might as well just use them. I don't care about looks, I would even kludge two different caps together to make one with close enough values, if I had the right ones. I just want to get this thing fixed, and working.
I'm fully aware that they are old, but they're new stock, so I trust that they will last at least for a little while. Which capacitor style am I dealing with anyways? Is it really ++ with - on the other end? Or is it +- and the third wire for structual support only? See attached picture of the location they're supposed to go.

Dave Wise:
It's not 75V, it's 7.5V .  (Or 7,5V depending on where you live.)  I would sketch a partial schematic, and if I was satisfied that there was no compelling reason to keep the exact original capacitance, I'd throw in a couple of new 1000uF parts of whatever voltage > 7.5V that fits the pad spacing.

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