Most TVs will demagnetise themselves, just turn them off for a few hours and switch back on.
If you have no speakers near, by near generally no more then 2ms in any direction. Try rotating the TV around and see if that improves it, the earths magnetic field can affect TVs.
Then move the TV to another location to see if there isnt any magentic fields around, it sounds like there are. This can be speakers, appliances like fridges, cookers, microwaves, phones, boilers even wires in the wall. So if it happens check to see if any things have been switched on.
When you move the TV, turn it off for at least an hour then switch it on and see if that improves it.
If you have no speakers near, by near generally no more then 2ms in any direction. Try rotating the TV around and see if that improves it, the earths magnetic field can affect TVs.
Then move the TV to another location to see if there isnt any magentic fields around, it sounds like there are. This can be speakers, appliances like fridges, cookers, microwaves, phones, boilers even wires in the wall. So if it happens check to see if any things have been switched on.
When you move the TV, turn it off for at least an hour then switch it on and see if that improves it.
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