Tv using power supply unit EAY62810301.

No back-light/sound ok.

No dc voltage measured at P801 led plug.
New board did not fix.
Remove display panel.
With face up, panel will hinge up. (after removing all trim parts) Place folded towels beneath, to prevent strain on tcon ribbon.
Fold other screens up and over on top of display to keep them in right order. Including white background reflector.
Check each series led string with 2*9V batteries and series resistor, minding marked polarity.
Circuit consists of 3 strips of 7 leds all in series.
One bad led disables all .
Check each led of bad string. I used 18V and 1K ohm.
Replace strip or jumper (short) bad led. I just jumpered the bad one that was on edge of panel. (first in string).