Just to shar share my experience below.
I had my iPad working well in the past 2 years till last week I face the battery 'not charging' situation. I referred to web for other people's comment and still no way out after trying all the possible tricks.
So I decided to look for some repairing service from some small store which is specialize in repairing apple product.(not authorizes apple repairing party).
First store told me that I need to change my connector which will cost me about USD 80 with the condition to leave the iPad with them for 3 days. Concerning the data privacy, I rejected even I would like to spend the money to fix this. Later on, a lady from another repairing booth come to me that their engineer could fix it. So I took a trial.
Finally he checked the connector and it seems no problem to the connector's pin problem. He opened the case and check inside, he found the problem that there is a tiny pin inside the iPad is damaged. So the real problem is repaired with 30 min. He told me that it might caused by serious vibrate, like dropped to ground, and cause this problem, not the connector that most of people always think of if.
So, just to share with u. If u had this 'no charge' problem with many ways to fix it still no success, then u might think whether your iPad used to drop on ground. If yes, you might need to think of the above situation. Hope it helps.