Blue light, black screens, nothing else
A friend gave me his 3DS XL since it was having problems reading game cards. I was able to fix that easily. After that I opened it up just to clean the inside since it's pretty old and dirty. After I reassembled it, it wouldn't turn back on. The blue light turns on and stays on, the screens turn on but stay black, and nothing else happens. I double checked all the connections on the inside and they all seem fine. The battery is super bloated, so I assume it's a power issue. I tried using my own battery but it still had the same problem. I tried turning it on with and without the SD card, and with the charger plugged in. When I plug in the charger without the battery, the orange light turns on for a few seconds, then turns off. The 3DS doesn't have homebrew, it's all vanilla. Since it's not mine, I'm willing to do everything I can to fix it, even if a part needs replacing. Please let me know if you have any recommendations.
EDIT: I tried booting the 3DS in "safe mode" by holding L+R+A+up on the dpad. The same thing happens, but now the yellow wireless light is on too.