Help analyzing busted subwoofer

[double9s]

I've had a JBL 12" subwoofer (PB12 I think is the model #) for several years now, always loved it. A couple months ago, I noticed that the volume had to be up pretty high to keep the subwoofer from going into standby mode (green light on front turns to red light when there are no sounds for awhile). Now, no matter how loud I turn up the receiver, the lights on the front of the sub just flicker back and forth between green and red, and the sound that comes out is very static-y, and just sounds broken.

I'm not much of an electrician, and I was wondering if there's anything I can do to check for problems with this sub before I spend a couple hundred more to get another one since I'd hate to spend all that money for something that could be a loose wire, and atleast something easily fixed.

Any help is greatly appreciated and I can supply any info that might help.

 

[dbpolk]

Take the amp out of the enclosure. Look for anything obvious like loose connections or wire, burned components, etc. If you can't see it in a couple minutes there is most likely very little you can do unless you are an electronics repair troubleshooter. To fix electronics is an art. There is very little a person without training and years of experience can do nine times out of ten. I am an electrical engineer and when my tv goes out I go and buy a new one.

 

[double9s]

Can someone recommend a better place to look for info? I'm not really getting any help here. Though I appreciate the one response I got, I'm not ready to give up just yet.

 

[ironlung]

I'm no sub expert but you may try this:

Can you switch the sub to always on or triger it on with a 12v signal from the receiver? I have read in the forums that line signal auto on is not the best. Some movies have long peroids of no sub signal and the sub will switch off and be caught off guard when the signal returns.


Good Luck

 

[j_garcia]

These amps are well known for failing. JBL's mass market sub amps at the time were absolute crap (they bought them from someone else). I wouldn't bother trouble shooting it, I would toss it. Someone else recently had an issue with one and JBL's response was that the amp manufacutrer had gone out of business completely and that there was no replacement or repair plan. They did however offer a discount on the purchase of a new or refurb sub from the factory at a discount.

 

[bandit]

Just a note on the "auto on" feature of most sub amps. When most of these amps (unless you are talking about the expensive elite) don't actually completely shut down when not in use. Most simply disable the audio signal path- but yet the power supplies remain on line... After all - they are powered up enough to monitor whether or not a signal is present and I think few have multiple power supplies for this function as the almighty dollar influences many of the design decisions.... just my .02 cents..

Bandit

 

[double9s]

Great info guys, thanks.

I contacted JBL and they pretty much confirmed what you said, that it would be impossible to get parts to fix my current sub. However, they're offering me an awesome deal on the equivalent model, the JBL SUB 12, $168 for a refurbished version or $190 for new. I was wondering if anyone has any experience with that model and knows if it's any good?

Keep in mind the price in reviewing it as I know it's probably far from impressive to any serious audiophiles. Also keep in mind that I was happy with the previous JBL model I had before it broke, so if this new one is almost exactly the same, I should be happy with it too. One major difference is that my model is floor firing while this new one is front firing.

Will that make a big difference?