After completing your schematic-guided repairs, do not just plug the board into the TV. Test it in isolation.
While a full, official manufacturer schematic is not publicly released, you can find the following technical documentation and repair resources: Technical Specifications & Reports ps42419ha schematic work
The schematic revealed a critical bottleneck: a specific resistor responsible for feeding start-up power to the PWM controller. On the board, it looked fine. Under a multimeter, it was "open"—electrically dead. The Culprit : A single faulty resistor and a dried-out main capacitor. After completing your schematic-guided repairs, do not just