LG-50UH5500 flashes on for a moment but doesn't show a logo. Not LEDs?

LG-50UH5500 flashes on for a moment but doesn't show a logo. Not LEDs?

I'm trying to diagnosis and repair my sister's TV. I've already read about the common issue with this and other LG TVs - bad LED strips, but don't want to make any investments just yet.

ANSWERS: