My 3DS shuts off when the top screen is pushed back too far.

My 3DS has been doing this for a few years. It turns on, works almost perfectly except for this. When the top screen goes just past a 90 degree angle, it shuts off with a loud pop sound. I don’t know what this is or what causes it, please tell me. Also let me know if it is fixable at home or if I need to send it in to Nintendo (it is out of warranty). Thank you.