TV LG 42LM615S-ZE

Hello, I purchased such a television in June 2013 which, during the viewing of a series last week, suddenly turned off the picture while leaving the sound on...? After a few hours of rest, several "unpluggings" and "repluggings" and then "fiddling" with buttons, the picture returned for 2 days. Since then, "here we go again"; each time I turn it on I can see the TV menu with the time, then the picture cuts out.
Since it is no longer under warranty, before incurring any costs with customer service, I was advised to seek information online. If someone could advise or inform me, I would be grateful. Thank you in advance. Best regards, Stéphane.