Partially dead after replacing LCD and digitizer.

I have a problem with my iPad 3 4G.

After replacing LCD and digitizer, iPad "won't boot" up. The device looks like dead (LCD and digitizer isn't working, no sound when connected to the power supply), but after connecting to a computer, I can still sync files and charge the battery. I tried to reset (buttons still works), restoring to factory settings etc., but nothing works. I remember, when the screen was plugged out, I felt a smell from the motherboard. Is it possible to burnt something?