Studio 1537 LED black screen, need inverter?

My wife spilled a few drops of soda on her Dell laptop LED screen.  Soon after, the screen went black, but you can faintly see images. When I plug into external monitor, it works fine, so it's not video.  I have tried the "unplug battery and hold the power button down for 60 seconds and that didn't work.  I took out panel and there doesn't seem to be any liquid damage, but I'm not an expert.

I can swap the panel or inverter, just don't want to throw money into something that won't fix it.  Local shop wants $250-300 and I'm not paying that just to fix a panel or inverter.