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My JL Audio sub is dead. What exactly happened?

So at my wife's request, I hooked up a Roku to my main system. Roku is a device for internet streaming movies and tv. The connection between the Roku and my preamp, a Meridian G68, was a 12 foot optical cable.

The first night, I hook up the Roku and it works perfectly.

The next night, I move some cables around, then I hook up the Roku again, exactly the same way as the previous evening. I get picture but no sound. Weird. I pondering what I might have done wrong when out of the speakers... POP. POP! POP!!!

Uh oh.

I dive for the amps, switch them off. The POPs stop immediately. But...

Now there's a TERRIFYING HIGH PITCHED PULSATING NOISE coming from somewhere in the room. I finally realize it's coming from the sub, a JL Audio Fathom 113. I dart across the room, switch it off.

I stand frozen, savoring the final moments of the fantasy that maybe things aren't that bad.

Here are some questions in no particular order...

1. I suspect the amp in the sub is fried. Does that sound right?

2. Where did those POPs come from? Could a damaged optical cable do it? Or maybe the optical cable wasn't fully seated?

3. Do I really have to ship this 150 pound sub to Florida? Or do you think there's any chance of finding someone local to fix it? (I'm in L.A.) The sub is out of warranty, btw.

4. I tried to take the panel off the rear of the amp (I know, lethal voltages inside) with the thought that maybe I would just bring the amp portion of the sub to someone local to fix. I removed about 12 screws from the rear panel and still it doesn't budge. Why can't I open this thing?

If you have any suggestions, I'm all ears. If not, thanks for reading.

Bryon

P.S. The rest of the system appears to be fine.
bryoncunningham

Showing 2 responses by jlithen

jlithen
2 posts
 
Just repaired one.
The manufacturer has apparently used very low quality capacitors from CapXon. They are also 85deg.C caps, lame.
Not sure if this is intentional by JLaudio, or if they just did not know how bad caps the Chinese manufacturer used.

Deadness is specifically due to a 100uF 35V cap at the standby power supply failing.

I replaced all CapXons with high quality caps, like 125deg.C ones, Panasonic FC, Rubycon ZL and some Sanyo ones too.

The Bipolar cap were still fine in the one I fixed, but I am thinking about replacing them at the same go.

Also getting the amp module out is a bit tricky.
You have to remove the driver (screws are under the surround of the woofer) and then carefully hammer out the sub module with a mallet and sturdy piece of wood as an extension. It is very heavy, do not let it fall.

I have lots of photos of how to do this, I cannot attach them here but maybe on DIYaudio.


jlithen
2 posts
 
Yes, it is horrible.
If the 4000€ sub was 5€ more expensive it would work 3x longer.

It is else very sturdy and the PCBs are of excellent quality!
So there is potential.
If I find some suitable contact information I can try to talk to them.
My goal in life is not to complain, but rather try to make things better.

But those who spent big money on these I can understand that they are angry.

I want to help people who want to repair theirs. It takes a couple of hours, but good caps like the ones I used cost around 30€, so you are not ruined. Even the 105deg.C ones I mentioned will work for very long in this sub! The most critical ones I used 125deg.C though.

Funny is that some of the originals are also 105deg.C, but not the one at the standby power supply. Which is for certain the most critical one!

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