I have a ipad 3 with ios7.0.4. Here is my problem, when i hook up the usb cable to charge my ipad it shows my ipad is charging. It is only when the ipad goes to sleep or when first turned on does it show not charging. Unplug and plug back in and it shows charging. I have replaced both usb and ac adapter. I have tried rebooting with home + lock button. Any ideas would be helpfull