if you are experienced with tvs and electronics and are aware of the lethal voltages present even with no mains conencted, open the set and check with a multimeter for an open resistor or leaky transistor on the CRT neckboard; could also be bad joints on the solder there.
if none of that makes sense, get it to a tech or you may well make it worse or do yourself an injury
romko
January 2007