My phone only works when charging.

So one time my phone stopped working. It only works when I am charging it. I tought there might be something wrong with battery so I replaced it, but the results were same. That led me to conlusion that my motherboard was broken. So I replaced it. But the results were still the same. I also have 2 charging daughter boards but changing them doesn’t do anything.I don’t know what else could be broken. I would really appreciate any help from you.