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Advice Wanted, JBL Subwoofer E250P, fire on Amp Board :(

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Way2Cool

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Hello All,

I have a JBL Subwoofer model E250P made around 2007.

The output power to the speakers stopped earlier this year.. I had a smaller Sub and swapped them as a temp. measure.

So today I removed the Amp assembly / input panel just to observe if there was something obvious like a fuse or something like that.

The only fuse is still good.. but there was a fire inside. A blue barrel looking thingie with a cross hatch on the end facing up appears to have burned up and leaked, then possibly caught fire.

So I'm wondering.. the circuit board is burned on one side, but maybe repairable, and the part might be replaceable..

Could I just clean up the mess, buy a part and install it for testing? or is that dangerous?

Everyone jump in here and add your advice please. I'd love to send it somewhere for repair but .. I work at JBL (Harman) and speaking with the new E Lab guys.. they don't sound very promising.

I'll see if I can add a few photo's of the questionable areas and parts..

HERE'S THE BACK SIDE OF THE BOARD:

IMG_20151018_162815.jpg


CLOSER VIEW OF THE BURNED AREA:

IMG_20151018_163723.jpg


AND HERE'S THE LITTLE BLUE CULPRIT ON THE OTHER SIDE :

IMG_20151018_163824.jpg


IMG_20151018_162741.jpg
 
The component that is toasted is a non polarised capacitor, rated at 100V with a value of 6.8 uF (MicroFarad). You can give it a shot, clean up the mess and carefully check that when you replace the capacitor that you reconnect all of the copper traces to going each pin. Use small pieces of insulated wire, in a point to point fashion, from the next closest components solder pad, if you need to cut any burned traces back. You may be lucky and this is the only issue, but I think that you may have other damage to deal with as well.
 
Thanks Mr Wolf..

I'm trying to find a fresh board or complete assembly too, but it's not likely.

What advice would you give for trying to clean up that burnt mess? IE any specific chemical to use or to avoid?
The damage looks a bit like caked up corrosion as well.. like something leaked and then caught fire.

I do want to go at it slowly and carefully just in case this is my only option.
 
You probably have a mix of things to clean up, soot, burnt resin, burnt solder mask, leakage of electrolyte from the capacitor etc. I would start by removing the component and then with a good scrub using an old toothbrush and some high purity solvent/ Isopropanol. Then see where you're at with the burnt board. You may need to cut some of it away, if you're lucky, just the surface layer with something like a dremel if it's really bad underneath. More important though is that the component can still be mounted in some fashion and that the tracks going to each pin are either kept intact or, as I mentioned earlier, bridged with some short lengths of insulated wire to the next closest component's solder pad. Use a good quality replacement capacitor, something branded from Panasonic, Dublier, Rubycon etc. Stay away from the cheap chinese capacitors...
 
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