TV doesn't turn ON

I would like to ask for help to identify what is wrong with my TV. When turning on I hear relay tick and after sec TV switching off (again relay tick). Red led/stand by is ligthning. I thought it might be an issue with motherboard so I have ordered from second hand but when I changed, the same issue appears. I have measured voltage on my power board and I found several volage difference. Can you please help me to identify if the power board is broken or T-con part or at the end panel. I would like to fix it as it's still quite new TV. Thank you Peter.