Sound intermittently dropping out with new TV

[Ann187]

Hi, been using sky stream for 18mths + with no problems. Have changed the TV and now having intermittent but ongoing issues with sound dropping out when watching anything via sky - TV or netflix etc.

Have changed the HDMI cable and restarted the puck and the issue is ongoing.  
Sound is restored when turning everything off, - TV and Sky puck - waiting and restarting. 
Sound can be ok for hours or days, but then drops out again. 
Amazon Prime via a new TV is working properly.
No issues with the picture.

Any suggestions on how to stop this happening with the new TV. Reconnecting the old TV and no sound issues have occurred. 

thanks

[peter-marlow+1966]

Have you  tried the sound settings  on  the  tv ? To see if it is that 

[Ann187]

Yes, sound always works for Amazon Prime and sometimes for TV and apps via sky, but don't know why it intermittent drops the sound completely