There is problem with the LED string that is connected to pin 3 and pin 4 of the LED connector, that Voltage reading on pin 3 Cathode return is way too high. You need to verify the Voltage reading again on pin 3 of the LED connector.
The IC Voltage boosters are working otherwise you will not have those High Voltage on the LED + pins.
ok i'll double check my readings again. i see the output voltages for LOW and HIGH labeled on my PSU at 145V and 218V. How can i tell what the cathode return is supposed to be?
1) TV OFF.
2) Remove the LED connector.
3) Set meter to over 200V scale
4) Keep black meter probe on chassis.
5) Put red meter probe on pin 4 of the LED connector on the power supply board.
6) Turn on the TV and see how high the Voltage jumps up too and wait 10 seconds to see how low it goes down too.
7) Repeat step 5 ~ 6 but move the probe to pin 3. Do the same again on pin 2, pin 1.
All these posts where obviously some LEDs are faulty. You should have stripped out the screen and powered the set up on its back where you would have seen faulty non lighting LEDs.
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