iPad completely non-functioning after repair. Fuses? Power relay?

I disconnected both the LCD and the control board cables while the device was on. I know -- stupid. This was not my first time taking apart the iPad. The reason for tear-down was to fix the fact that a bar of about 1 cm across the top of the digitizer would not accept touch. I finally decided to attempt the repair because upon upgrade to iOS 8, I could not get past the new OS setup screens. The 'Next' buttons are all in the top right corner, where I could not touch, and the screens do not go into landscape mode, my usual solution to pressing those buttons.

After 'repair', the iPad does not turn on, nor is recognized by iTunes, nor powers on from the wall outlet. I have left it plugged in overnight, and left it unplugged overnight.

What I did:

1. Forgot to power device off

2. Used hair dryer to quickly melt the fairly weak adhesive I had used on the previous disassembly.

3. Remembered the device was still on.

4. Attempted to turn off, but power button was not functioning. It should have been, as it was a day prior, but this day I had not tested it. The only thing I can think of that was during the disassembly that could have caused this is the heat.

5. Instead of stopping, I forged ahead

6. Connected iPad to iTunes and all was good

7. Disconnected iPad from computer

8. Disconnected LCD screen while it was on and lit on the 'Hello' screen for iOS 8.

9. Reconnected LCD screen. I could see that the display was still working but the backlight was off.

10. Disconnected LCD screen again.

11. Disconnected control board cable.

12. Reconnected control board cable and LCD screen. Nothing on LCD screen. iPad entirely non-functioning.

I cannot be sure that a hard reset using Power and Home buttons is not working because the power button was not working at the beginning of the disassembly.

What could I have broken within the iPad? Are there more fuses than the LCD screen fuse (I'm not sure where it is)? My dad suggested it could be the power relay. I don't know too much about electrical wiring.