How to troubleshoot a subwoofer that turns off by itself.
WARNING: There is a risk of hardware damage. Before diagnosing the problem, turn off the subwoofer. Do not connect or disconnect any cables if the subwoofer is turned on.
IMPORTANT: If model-specific information is needed, refer to the instructions supplied with the product. Manuals are posted on your model support page.
- The subwoofer may have an energy-saving feature that powers the amplifier off if there is not a signal after a specified amount of time. If this is the case, set the Power Save switch to the OFF position to prevent the subwoofer from turning off by itself.
- Check the cables or speaker wires for proper connection between the subwoofer and the main unit.
- If using an active subwoofer, ensure it is connected to a working AC outlet. To reduce the possibility of an electrical short, do not connect the subwoofer to an extension cord or power strip.
- Check the speaker size setting in the Set-Up menu of the main unit. If the speaker size setting is incorrect, the subwoofer may not be receiving any signal.
After verifying these connections and settings, turn on the subwoofer. Check the volume level of the subwoofer. Start at a low volume and gradually increase the volume to determine if the subwoofer is working.
The troubleshooting steps listed above should resolve your issue. If you have completed all of the steps and the issue is not resolved, service may be required.  Go to Product Repair.