Water damaged ipad2, with new LCD and flex cable

I hope someone out there can help me. A friend of mine gave me his water damaged ipad 2 and I have tried to fix it. I am not a novice when it comes to repairs. When I first received it, I had no idea how it was water damaged, how long it had been turned off (if it had been), how long it stayed off or if it had been thoroughly dried out. When I first connected the ipad to my pc, I kept getting a message saying that the ipad was in recovery mode. I was unable to get it out of recovery mode no matter what I did. But the fact that the ipad was being detected but nothing was showing up on it led me to believe that the LCD was damaged. I ordered a new LCD and took a part the ipad. I changed out the new LCD along with a new flex cable (the old cable had corrosion on it where the cable is connected to the LCD, not the logic board). I connected the ipad back to my pc and itunes was able to detect it, update it and get it out of recovery. The ipad is functioning properly, but I am still not able to see anything on the screen. Does this mean that there is something wrong with the logic board or the circuitry? Or is it possible that I received a dead LCD or flex cable? What can I do to get this ipad working again? Please advise.