@cm20228 could be a bad power board/LED backlight driver or a bad mainboard as well as a bad T-con board. You will have to go ahead and take a look at those. Of course, there is always a possibility of a bad firmware.
Since you just bought this set, I'd contact the vendor and have it replaced/repaired under warranty. Do not try any self repair until you checked out what kind of guarantee you have on this set.