When I close my system, it stays shut off

My system faced water damage some time ago, but i went through the drying process. The 3ds wasn't on and I bought a new battery. after installing the battery the 3ds turned on just fine, but when i close the bi-fold of the 3ds to send it into standby, it will not come back on. If anyone could help me it would be greatly appreciated. Thank you for your time.