If it was me I would pull the chassis and clean everything up and replace the supply caps only in the intrest of protecting the power xformer. That is a Hi-Lite tube and the date code as jstout66 pointed out is 1976 so that might be the last time the set was ever serviced.
Give the tubes a bath and clean around the HV socket plastic, I remember as a kid that they were real good at making corona storms.

Go get even more stoked and replace the supply caps, everything else will fall into place.

Now that is a beautiful set! Great find!

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