The Sound bar switches to the USB input by itself.
To fix this issue, follow the troubleshooting steps below.
NOTE: Not all Sound bars have a USB functionality. To know whether your Sound bar has a USB port, refer to the operating instructions that came with the unit. Manuals are posted on your model support page.
- Insert an empty USB flash drive to the USB port of the Sound bar.
- Turn off the Sound bar and the TV.
- Unplug the power cords of the Sound bar and TV.
- Remove the USB flash drive from the Sound bar.
- Reconnect the power cords of the Sound bar and the TV.
- Turn on the Sound bar and the TV.
- Set the Sound bar and the TV to the corresponding inputs.
If issue still persists after following the troubleshooting steps, service may be required.  Go to Product Repair.