If it's out of warranty, and the TV is oldish and repair is too expensive, it's time for a new T&V.
I have a 55 inch model 55EC930V, the TV strikes and the LG logo illuminates but then switches off after a few seconds, Equinox have replaced the power and main board last week and returned yesterday and fitted a new panel, however the original fault still exists, anyone had this issue and any advice other than a replacement as LG are digging their heels
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