Blank LCD after replacement

I have two iPads (first gen, wifi) one has black and colored lines/ bars through a portion of the screen, but turns on and responds to touch. The other does not turn on and is not recognized by iTunes, so I presume that the LCD is fine. I switched the LCD's (along with digitizes) and the working iPads screen is now black: no backlight, picture, etc. I can turn it on and can hear the unlock sound when I swipe in the area near the slide to unlock. Many people with this issue seem to have damaged the motherboard, but I believe this is not my issue because I can reconnect the LCD with bars and it does turn on.

I have tried: Both LCD connector cables, powering off before the switch, hard reset (power+home), iTunes reset...

Is there anything else to try or do I have a bad LCD?