# Is this Capacitor Bad?



## Tony O (Mar 5, 2009)

Hey all,

I'm posting in general forum because at this point, I just want me to tell me this is either normal or it's a bad one. You should be able to tell by the pic, I would think. I'm mainly asking about the stuff between the two capacitors. It's looks like one of them must have burst but since I know next to nothing about this stuff (and the Capiticitors do not look swollen), I need someone with a bit more smarts to confirm.
thanks in advance,

Tony O


----------



## brucek (Apr 11, 2006)

I can't tell much from the picture.

Are you sure there is something that is leaking from the capacitor, and that it's not some type of glue?

Generally, capacitors don't just leak when they fail, they explode. The dielectric (insulator) inside can break down and then can only withstand so much voltage and then the DC will pass between the plates causing the capacitors electrolyte to heat up. This creates internal pressure that can cause the can to explode. Most larger capacitors have vents though (either plugs or stressed marks on the end of the can) to reduce the risk of an explosion. You can see on the ends of your capacitors in question that the stress marks (an X in the top) has no obvious bulging yet.

Anyway, we'd need a better picture.

brucek


----------



## robbo266317 (Sep 22, 2008)

It looks like glue to me. If they are mounted the way it is shown in the picture there is no way a leak could be flowing horizontaly around the one at the back.
Normally you would see an oily or white pool on the circuit board beneath them and the tops bulging or split.


----------



## steverc (Jan 5, 2008)

What BigBadBill said.


----------



## Tony O (Mar 5, 2009)

Thanks guys.

well maybe this will be more helpful. I've uploaded some newer pics to my own site:

http://www.santacruzbiofuel.com/gallery/view_album.php?set_albumName=album02

Let me know if those are better. I don't necessarily think that's an exploded capacitor but
out of all the capacitors on the various boards, those are the only two with that "goo" between them so I thought it would be the first place to look. I will soon post my tv "issue" but figured I'd get this sorted out first.

cheers and thanks again.
-Tony O


----------



## robbo266317 (Sep 22, 2008)

If you feel it you should find it is a silicon compound like silastic and will feel rubbery.
Its put there so the two tall caps wont vibrate and crack the tracks on the pcb during shipping.


----------



## lcaillo (May 2, 2006)

As others have said, this is just glue.

To determine if a capacitor is bad visually, you would look for swelling or venting at the top, or if it is leaking it would have fluid around the legs and perhaps black goo from corrosion on the leads on the other side of the board. Otherwise, you need to test it for capacitance, ESR, DA, or d.c. leakage.


----------



## Tony O (Mar 5, 2009)

Thanks guys.

I guess now I know at least that's not the place to start. I visually inspected all capacitors and NONE of them to exhibit any signs of swelling. I'm going to test the fuses and then probably post my specific problem. I've seen a lot of similar problems on this forum, but after reading about 30 pages of posts, I still don't see the exact same thing.

cheers
Tony O


----------

