iPhone 4S Only powers on with cable after battery replacement.

Hi there, I have an iphone 4S which I was having issues with the iTunes error 21 which indicates that the battery is faulty.

After replacing the battery with a new one and other working 4S batteries the phone still does not power on unless its plugged in.

Even still, I am unable to use the phone as im not able to restore it.

Ive inspected the board and cant find any signs of blown caps.

I have also replaced the dock connector to rule that out.

Anything else i have missed to get this issue resolved?