Battery and dock connector changed but phone not charging
I've got a customer which has a problem with her iPhone 6.
She told me that the phone doesn't charge anymore, she has brought it in to another store to get something fixed, they replaced the battery and the dock connector but the phone is still not charging.
Can you give me any advice on how to handle this and where to start to check what is broken.
So this is the case.
When the phone is plugged in, the charging symbol shows, even when I use my own charging cable and plug which are official.
I'm not sure what this could be, I would be pretty sure that the connector is just fine.
Could this be something based on the motherboard?
Is this a good question?