DSI XL won't turn on

I’ve decided to pick up an old and broken DSI XL to try and fix (because I always wanted to start fixing consoles) and then hopefully gift it to my little cousin. The seller mentioned that the upper screen is broken.

So I ordered a new screen and a solder for the speaker cables and here is where things got weird. When I try to open the DSI XL with the old screen, the bottom screen flashes, and then the console turns off. When I tried to install the new screen (without soldering the speakers because the soldering iron hasn’t arrived) nothing happens. The console does charge but when I press the power button it doesn’t turn on or flash or anything. Does anyone have any idea what the problem might be? I tried installing the broken screen again just to see if anything different might happen and it still does the same thing (flash and then turn off).