I have a mitsubishi 55 inch tv model ws-55313 i can hit power it will come on for a 20sec then powers back off what is the cause of this?

Hi my name is Roety,
I can help you with your issue ,
Most likey you need the convergence ICs replaced.
A repairman would charge about $350 to replace them
Voltage checks and a visual would be needed to determine exactly what is bad in your TV
　
　
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Thanks

I’m happy to help further over the phone at https://www.6ya.com/expert/eric_ab7c09ec01841771