iPhone 4s killing screens and going into recovery.

I have fixed a 4s for a customer and the phone had screen replacements before. It was working but had busted glass. I replaced the screen and it was good for a few days then the screen went blank and the phone went into recovery mode. I replaced that screen and a few days later again the screen went blank again and the phone is stuck into recovery again. Any ideas what could be going on? The previous repairs looked like they did a good job... no missing items. I dont see how 2 screens could go bad doing the same thing? I have never had any of my screens do this before. I may try a new one but I just wondered what else could be happening? Is it shorting out and dead? Did my repair do something? After the second repair on the iphone I turned it back on and it said it was disabled and then I turned it off and back on and it was back to normal like it wasnt in recovery? Any help would be great! I would like to get this customer back up and running! And yes I have tried resets, etc...