I found this solution on another website, my tv and sound bar turns on and off every time. Hope this works for you.
1. Plug in the optical cable
This step should be a no-brainer in this process. Without plugging in the optical cable to your Soundbar and your TV, there will be no connection made during this method, and the TV will not be able to transmit sound to the Soundbar in this way. So, make sure that the optical cable is plugged into both devices and that the plastic tips are removed to ensure a good connection.
2. Ensure that Auto Power Link is turned on
When using an optical cable connection, you will need to make sure that the Auto Power Link setting is turned on on the Soundbar.
This should default to being turned on, but if it is not, then all you need to do is press and hold down the left arrow on your remote. Once this is turned on, this should activate this input option and allow the connection to ensue.
3. Turn on the D.IN mode on your Soundbar
Again, this should default to being turned on, but in case it is not, you will need to turn the D.IN mode on your Soundbar by pressing the Source option on your Soundbar or remote. This is the digital input mode and is what sends the signal between the two devices.
4. Adjust the TV speaker settings
After you have ensured a stable connection with the optical cable and made sure that Auto Power Link has been activated (by default or manually), you will want to adjust the TV speaker settings.
In doing so, you will make sure that the receiver is the preferred audio source rather than the internal speakers. Otherwise, your TV speakers will be the preferred choice, and you will have to manage the connection to your Soundbar each time.
