This TV did have a burned out (blackened, actually) LED on one of the

This TV did have a burned out (blackened, actually) LED on one of the backlight strips. I replaced that whole strip, and all the backlights are now working/steady, with no blinking… unfortunately, there is no longer any picture on the screen. Before, when the backlights would flash on, I could see the LG menu and screen, but now there’s nothing, just a dark-gray screen.

So, it looks like something went wrong when I disassembled the screen to fix the LED strip, or when I put it back together. But nothing looks broken, and I was very, very careful. I’ve checked all the ribbon cable connections many times.

So, to summarize: all the backlights are good now (and audio still works), but there is no video whatsoever. HELP!