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Does it rise up if you disconnect the board to the Left of the power supply? That's the Ymain board, and it's the main load the power supply feeds.
but connect both and it blinks read 5 times or so and then turns off
That's enough time for the TV to turn on those boards..certainly the power supply is bad, but let's not damage the new power supply too. Did you do an Ohm or Continuity test from Vs / Va to ground on the boards ? Does the logic board's green led light blink once a second OR does it light up once, and shut down when the rest of the TV shuts down? It's nice to know that before commiting resources to the TV.
Ok, knowing that..the Ysus and xmain board are both suspect in damaging the power supply board and causing that voltage drop on it.
You should use your meter's beeper/continuity test on the power supply board's connection to the Ysus/Ymain plug, measuring the VS to ground/GND. If it's low/shorted, unplug the Xmain and see if the resistance shoots up. That means the Xsus is shorted. If it stays low, then the Ysus/Ymain is shorted.
Use the pictures below to help you with that low resistance/shorted test --