Bought an LG WebOS TV UK6570AUB last year. Has been working fine. Last night during an Amazon Prime show, heard a pop then sound was gone. TV diagnostics show tv is fine. Cable diagnostics say cable is fine. Sound fine via youtube and dvd player. No sound via cable box. Picture is fine. Anyone else have this issue? Is there a fix? Uninstalled/reinstalled amazon prime app. Very frustrating. Thank you!