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If the TV shows 'RCA2' and then turns Off, that's a rather puzzling thing.
Since this model of TV has two RCA ports, or port rows perhaps, then that may refer to a problem detected in the RCA2 board inside - probably, if so, a problem severe enough that the TV shuts itself down protectively, thus probably a short-circuited RCA2 board too, as well as simply 'defective'.
I admit I have not found any references to 'RCA2' as a diagnostic error message. Are you using the Hitachi TV's original remote control by any chance? If you are using a universal remote, then the RCA2 might not be an error message at all.
But anyway, one thing is quite clear: your TV turns itself Off. Therefore it most likely needs repairing.
Do you wish to do self-repair on it, or would you rather have the repair hired out?
Let me know, so that I may advise you as appropriate. Thanks.