My 3ds won't turn on after charging even after battery replacement

I recently found my old 3ds xl and I tried turning it on to see if I could relive some memories, to my surprise it didn't turn on so I plugged it in to charge for about 4 hours then tried again and it didn't power on, I then tried turning it on whilst it being on charge and it worked but as soon as I unplug it turns off. I ordered a new battery and replaced it, then it was the same problem I don't know if the motherboard is the issue or the battery. Can anyone help?