Question about JBL SCS125A System

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Thumping when not hooked up

My sub is plugged in electrically but not hooked up to the stereo and it is making a "heartbeat sound". I tried a couple different surge protector strips so that is not the problem. Blown fuse? This is a confusing problem. Any ideas?

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First thing to check are signal cables but broken fuse telling me that problem is 99% in sub power supply unit or the amp.If you have a voltmeter and if you KNOW how to do it dissasembly it and check DC voltage on a speaker conntacts.If there is any DC present your amp is worn out.But this can be VERY DANGER because 220/110V is there so if you are not 100%sure that you can do it DON'T!!!

Posted on Mar 23, 2008

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