My 3ds won't boot

I took my ds apart and when I put it back together ( and I made sure multiple times that I reconnected everything) and I turn it on the blue light comes on saying it's on and then after a few seconds you here a pop from the speakers and it turns off. I have managed to get it to boot a few times bit even then it will turn off at random with a poping noise. I cant seem to figure out whats wrong so before i send it in i wanted to get your guy's opinion