Screen shows only apple logo after replacing LCD/Digitizer?

After replacing the LCD and digitizer screen, the iPad didn't seem to power on. However, it hasn't been used or charged in over a year or more. So I plugged it in and immediately saw an apple logo shown, clearly on screen. Unfortunately, the logo is the only thing that comes up and it seems to cycle from the apple logo to a dark screen and back without any prompting. The logo remains on screen for approximately 7 sec, then the screen goes dark for the same amount of time before the logo shows up again. This is while it's plugged in. The screen remains dark when unplugged.

I've taken it apart again, disconnected the battery, and checked all the connections, before putting it back together and finding the same result as before with the cycling logo and nothing else on screen.

The original damage was from someone intentionally smashing it. Which causes me to wonder if there's some internal damage that I can't see? However, all parts and components appear to be in good condition and are all in their proper places.

Any suggestions or insights would be greatly appreciated!

Thank You!!