I'd say it could be a connection issue via the motherboard. However, I believe you when you say you have overly checked. So, my next question is where did you get your dock connection? But seeing that you are having the same issue with your old connection, this would be my suggestion. 1) Make sure your dock connection is clean. 2)Update to the most recent Itunes 3) Use the updated version of itunes to update your phone to most recent If connection does not work after that try 4) Restart your phone 5) If restarting does not work, Reset the iphone. -Press and hold the Sleep/Wake button and the Home button at the same time for at least 10 seconds, until the Apple logo resets. Let me know if this has helped
Those having issues with making/receiving phone calls go through these steps if you need help with understanding how to do a reset and if all else fails a DFU mode reset, I can assist. I am Apple Certified and have access to all service guides. 1Verify that your carrier name appears in the status bar, at top left of the display. 2Turn Airplane mode on, wait for the to appear in the status bar, and then turn it off again. 3Reset Network Settings: Tap Settings > General > Reset > Reset Network Settings. 4If your iPhone is in a case, try removing it to ensure that the case isn't interfering with the cell signal strength. If these dont work, Contact your carrier to find out the following: -If you are in an area with network coverage. -If there is a network outage. -The account is properly configured to your phone. Try to restore your phone and set it up as new. If the above does not work try this Apple Support Article on Troubling a No Service Iphone. http://support.apple.com/kb/ts4429 Let me know if this works.
Depending on the issue. It could be dead pixels. Try to take a warm cloth and gently press on the areas that are having the issues. It may be a firmware issue as well, I have posted a link to a youtube video to help you with it (if its what it is) http://youtu.be/9DPcZ1LBxf8 I would also say it could be an internal problem, where the wires are a little loose. If you have the proper tools and it will not mess with your warranty, I would take it apart and check the connections. If none of these work. Try taking it in to get repaired. But Id guarantee its one of these. Corey