JBL Northridge E-Series E250P

[enduser]

I have a JBL Northridge E-Series E250P self-powered sub-woofer system. This past weekend, the sub-woofer while playing music started generating some random extremely loud popping noises. This was the first sign of trouble in the 7 years that I have had the system.

While powered down in the auto standby mode, without cause the sub would randomly wake up and generate some mad popping sounds then a while later it would again return to the auto standby mode. This cycle would repeat randomly unless the system was powered OFF using the rear AC power switch.

When I removed the PCB I immediately noticed heavy burned marks on the power section specifically by the +/-15VDC voltage regulators.

Closer inspection showed that the board was populated with caps from CapXon, LASTING, and Su'scon. Since the popping sounds are related to faulty capacitors, I started my troubleshooting by removing each electrolytic cap and tested each one using my LCR meter. My ESR-micro v4.0 has been ordered and is en route

The LCR meter showed that both CapXon GS series caps on the +/- 15vdc rail were open. The LASTING brand cap even though it only filtered a low level signal was found 27% out of tolerance. The remaining Su'scon cap used in a critical power conversion section was also open.

Only the following components listed below were found faulty on the board, but all capacitors regardless of their condition were replaced using EPCOS, Rubycon, United Chemi-Con, and Xicon brands. No reason to deal with this BS again.

C4,9 22uF/25v 20% - CapXon - open
C12 330uF/16V 20% - Su'scon - open
C37 47uF/16v 20% - LASTING - out of tolerance

I re-assembled the unit verified that all popping sounds and random wake-up have now ceased and that the system works as designed.

[weirdlookinguy]

Re: JBL Northridge E-Series E250P

Nice save, enduser. I like harmon/kardon stuff (JBL's parent company). The plate amplifiers inside subwoofers tend to run very hot and cook cheap or 85C caps.

[enduser]

Re: JBL Northridge E-Series E250P

UPDATE:

I got my ESR-micro v4.0 today. I fired up the micro and I decided to test all the caps that I removed from the JBL sub. To my complete surprise all the caps that tested good using the LCR meter but were replaced anyways just in case are in fact bad when tested using the ESR meter. Not only was the ESR rating exceed by 80% or more on most of the caps removed, a great number of them also measured less then half of their printed capacitance. This handy tester proved to me that using an LCR meter is like doing half the job.

[Chickoo]

Re: JBL Northridge E-Series E250P

Hi, my JBL E250p subwoofer rendomly poping and turning on green indicator without any music on. This was happening many times. Recently while it was running, suddenly with popping sound it just turned off. After disconnecting for few minutes and turn on, it worked few minutes and stopped same way.
I open back panel and notice burning spots right behind three caps. Please see pics. Can someone help how i can fix it. I do many fixing stuff myself but never deal with capacitors or amp fixing. Your help will be greatly appreciated.

Thanks in advance.
Chockoo