Help with Capacitor

[pllasma]

I have a capacitor from a subwoofer with the following info:

Samxon
3300uF80V
LP (M)
85C -NEG

Or view my attachment..

There is a brown/tag substance at the bottom, does that mean it is bad?

Also, and more importantly, I cannot find this exact capacitor anywhere, how would I find the exact replacement or is there an alternative part I can get?

Thank you,

Dave

[budm]

Re: Help with Capacitor

Bad glues that will turn brown and become conductive and also eat away traces and wires, if you see it any where on the boards you must remove them.

[pllasma]

Re: Help with Capacitor

Bad glues that will turn brown and become conductive and also eat away traces and wires, if you see it any where on the boards you must remove them.

Can I remove the bad glue and salvage the capacitor? If so do I need to add new glue?

[SteveNielsen]

Re: Help with Capacitor

It doesn't need glue. That was only to hold those parts in the board before it went through the soldering process. Test the cap if you can. It won't necessarily be bad because the glue was there.

[pllasma]

Re: Help with Capacitor

Can I test it still attached or is it better to remove the capacitor first?

[SteveNielsen]

Re: Help with Capacitor

Better to test it removed so no other parts of the circuit it's in will affect the measurements. What do you have to test it with?

[pllasma]

Re: Help with Capacitor

I was able to test both capacitors. Here is their behavior. Please excuse my lingo I am NOT an expert at circuit boards. The first capacitor went up to 20 ohms then I reversed the voltmeter leads it went down to 0 ohms then up to 2 ohms and stopped.

The second capacitor went up to 10 ohms, when I reverse the leads on the voltmeter it went to 0 ohms and only up to 2 ohms before it stopped


Both capacitors have the same exact specs on the outside.

Does that sound like normal behavior for those?

[SteveNielsen]

Re: Help with Capacitor

A DC ohms check like that is not a reliable test. All that tells you is that the cap charges up to some degree and isn't a dead short or open circuit but nothing about the actual capacitance. You need a capacitance meter capable of measuring that high of a capacitance and preferably tests ESR too. Then you can get an idea of the caps condition.

[budm]

Re: Help with Capacitor

Is the sub woofer still working?

[pllasma]

Re: Help with Capacitor

Is the sub woofer still working?

For about six months, it was working, but making either high chirps or a low hum. 2 weeks ago it stopped working but still makes the noises.

[stj]

Re: Help with Capacitor

show us the rest of the board - both sides.

[pllasma]

Re: Help with Capacitor

show us the rest of the board - both sides.

I will once I get home later today..

[pllasma]

Re: Help with Capacitor

Had a meter at work that tests for capacitance. For the 3300 uF capacitor, it's reading 2940. Is that an indication that it could be bad or is that within normal range?

also hooked up a 1.5 V batter to charge the cap and it's staying pretty much at 1.5 draining very very slowly