Right but if it was me I would be verifying that for sure with another input, if you say its TV that is OK , I will continue that way now you need to follow a procedure and the procedure is this assuming you are using HDMI
OK HDMI loss is a very common issue with modern sets and there is a procedure to follow, the first thing to do is >>try different hdmi products not just one to eliminate the product as the issue then>>
1)Un-plug the set from wall-power wait 5 mins then re-plug back in again try HDMI again
2) If there is a reset to factory default in the settings menu of the TV please use that try the HDMI again
3)If still no go go to the LG website and look for any firmware upgrade for the set under support for your model make sure you have the latest version of firmware.
If all fails then the main-board will need to be replaced (assuming the set is not under warranty) let me know when you get as far as that and I will advise further
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