If you repair TVs you use prior experiences and the Service Manual to get into this repair. But this is the Internet and folk want to know what board or chip to replace. That's not possible today without getting it wrong a lot of the time. So you're back to the old TV repair method of get the service manual, follow it's troubleshooting tree then change out parts as it calls out.
Tv will not turn on. It did one time but went off not longneck after turning on.

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