I noticed that my 2011 MacBook Pro 17 in would not show a "green " light on the charger's "L" tip. I replaced the Mag Safe board with one that I assumed was good purchased from Ebay, but although the battery shows a good state of charge, the "L" tip on my charger doesn't light up. The computer though starts up. Any ideas as to where to go from here? Thanks for any advice you might have.