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Powered 12 inch JBL subwoofer cycles red and green

I have 2 JBL 12 in subwoofers hooked to my home theatre. Both have worked fine for the past 3-4 years. Given the understanding that the front LEDs are red when the system is off and green when the system is on and working, I now have one that starts off ok then cycles from red to green in an even timing pattern. Thoughts from anybody what in the amp section would cause this?

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ice man
  • 68 Answers

SOURCE: jbl pb12 subwoofer

yes it can be repaired. but i need more details on this...

Posted on Apr 23, 2007

  • 2 Answers

SOURCE: jbl PB12 powered sub woofer problem

These subs have had many problems, all associated with the amplifier section. PB 12's with an "M" as part of the ser. no. were assembled in Mexico and these are the ones with the amp problems. JBL fixed mine and sent it back no charge, BUT it cost me nearly $100 to send it to them in the first place. I have another one that has had no problems at all. Try sending it back for repair. At best you'll get a rebuilt unit back, at worst a substantial discount from the company for a new sub.

Posted on Aug 09, 2007

  • 138 Answers

SOURCE: subwoofer isn't working

If your wire connections are normal then the problem is due your woofer speaker. Its your subwoofer circuit error and must be repair thru replacing the damaged Component in the circuit

Posted on Dec 09, 2007

  • 1 Answer

SOURCE: jbl subwoofer PB12

I had the same problem...replaced the C42 capacitor with one that I got from RS...fixed everything and all is well again. I only have moderate soldering skills, too, so if I can do it, so can you

Posted on Dec 01, 2008

SOURCE: when i plug in my subwoofer it has a constant hum

Check to see where you are plugging it in. Plug all equipment into the outlet strips powered by the same AC outlet. Or use a direct box. Check your cords also. And lastly, return the product if you are under warranty and get yourself a new one. If the problem is still occuring, it probably has to be on your part, not the product. So try one of those examples before you return it.

Posted on Oct 15, 2009

  • 11361 Answers

SOURCE: JBL PB10 subwoofer sounds distorted and lights on the front flash

More likely to be the Class D power amp module, but you should look through the service manual to make sure all the parts are installed correctly. My PB10 AMP module went out and you cannot get one anymore.

Posted on Nov 10, 2009

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if your serial number starts with ha then it's probably a bad capacitor C72 . 6.8uf 100v np electrolytic. replace it with a higher voltage capacitor of the same value.

Mar 10, 2007 | JBL PB12 Subwoofer

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