Panasonic SC-HTE80 disconnects from tv

[Harry Arcos]

After connecting with the tv, the sound is fine for a period of anything between 5 minutes and 3 hours, but then suddenly disconnects and reverts back to the tv speaker. This happens whatever method is used between the tv and audio system - HDMI - ARC, Optical or Bluetooth. It is not a problem with the LG tv and I cannot see any blown capacitors or dry joints within the unit. Any help appreciated.