There is a broken conductor strip or broken solder joint on the circuit board near the power input jack. do this: 1.) disconnect tv and open panel to expose circuit board. 2.) using a flashlight and magnifying glass, look carefully for this broken solder strip or solder joint. Flex board slightly if necessary to aid in finding the break. 3.) repair it using solder iron and flux solder and scratch copper conductor slightly to aid in "wetting" the solder fix.
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