TV will turn-on without picture for 15 seconds, then power-off.

Steps:

1. Press power button.

2. Red LED lights up and stays in a solid state.

3. Screen will respond with a completely black screen (no picture, no UI, no graphics).

4. After 15-20 seconds, TV will automatically power-down.

5. TV will repeat steps #2-4 for a few cycles.

6. Unit eventually turns off completely.

I tried:

1. Holding power button (with and without unit plugged in).

2. Holding power button + volume (with unit plugged in).

3. Unplugging the unit for hours, days and even weeks.

4. Using a new power outlet.

5. Unplugging all communication cables.

6. Uninstalled back panel and vacuumed/ compressed air all ICs/boards.

This issue occurred once before, but a power cycle solved the problem.

There had been no degradation or issues with the display itself.

I'm looking at the service manual, but nothing seems to fit my problem.

What do I do next?