Why is my replacement screen not working

Hi,

I recently replaced my screen+digitizer in my moto g phone. Both the display and the digitizer worked well (although the red was slightly less 'red').

There was a small area near the top where the touch screen sometimes worked, sometimes didn't. I removed and re-inserted the ribbon cable for the screen and then the digitizer stopped working. When I repeated it, the screen also stopped working, though the LED backlight worked. Thinking I broke the ribbon cable, I ordered a new one from another vendor.

This new screen also doesn't work at all (only LED works). But the touch screen works fine. I did an ADB screen grab using the USB to computer and I can 'see' what the phone screen background image is being trasnmitted to the screen, but I don't know if the circuit is damaged or this screen is bad too.

Any ideas would be greatly appreciated.

Thanks,

Nooman