Sony powered sub woofer quit working



Hello everyone,

I just signed up to this forum hoping to get some advice from the pros! I am definitely a novice when it comes to troubleshooting stereo equipment, but like to think I have a bit of common sense! So here is my issue:

I have a Sony powered sub woofer that "was" running off of a Sony amplifier. All of a sudden while watching a movie the sub woofer quit working on me. I have tried the following:

1. Adjusting the RCA cable jack, putting pressure on it from various directions, sliding it in and back out, hoping maybe it was a bad connection.
2. New RCA cable. I tried a few different RCA cables.
3. I took the sub woofer apart to check the input, everything looks fine, the metal tab that appears like it contacts the very tip of the RCA probe is in place. All wires are connected as they should be.
4. The fuse is not broken. Speaker is fine, no issues apparent. Circuitry looks OK just by eyeballing.
5. The settings on the amp are set correctly to power the sub woofer. ("tone-subwoofer-yes")
6. I tried plugging in the right (and left) stereo outputs to the back of the sub woofer, but I hear nothing at all. Not even the short crackle you might normally hear when plugging in a speaker.
7. Volume is turned up on the amp, volume is turned up on the sub woofer.
8. The little green light that indicates the sub woofer is powered on is lit.
9. I even took the cover off of the amp to check the sub woofer RCA output...all looks good

What has me stumped is that it just quit working on me while in use. I was hoping it was a loose connection on the RCA input jack, or that the fuse was broken, but neither seem to be the culprit. I don't know much about signals, so step # 6 had me slightly concerned. I was thinking that I "should" be able to hear at least something coming out of the sub woofer with the right or left speaker, but I don't hear even as much as a "crackle" when the RCA cable is connected, much less any sound out of the sub speaker.

I hate to fork over the $$$ at the worst possible time for a new powered sub woofer, but it looks like I might have to. If you have any other thoughts or suggestions, I am all ears. Before I buy a new unit, my plan was to contact a friend that has an amplifier and take the sub woofer over there to check and make sure it is the sub woofer itself, and not the sub woofer output on my amp.

Thanks so much for any help!

-Stuart Davenport


Audioholic Warlord
Get a cheap Dayton 1200. But first which system is the Sony? Model number if you can.


Audioholic Slumlord
You have done your trouble shooting logically and by the book. Unfortunately you have proved that the sub woofer power amp is fried. The class D amps in subs are the commonest point of failure in audio systems. They are miserable to trouble shoot and not worth cost of repair.

So yes, it is new sub time. If the sub is ported, you could buy an external amp and put terminals on the back of your sub. However Sony are not known for stellar subs, so this move may not be worth it.

What is your total system? If the rest of the system is reasonably matched an external amp may be reasonable for you.

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