I have a 2011 MBP 17" with charging issues. I just replaced charger with new oem and also replaced charge port and it still won't charge unless I push down on the plug. Doing so actually grounds the magnetic part of the charger to the case and it works. So I am assuming I have a grounding issue inside the computer. Checked the outside pins for ground with the magnetic part of the plug and I get ground. Checked those pins on the mbp and it's not grounded to the case. Any ideas?