I plugged in my friends macbook pro charger to charge my MBA at his house like I have done many times before but this time around I did not know that the charger was faulty but by the time he told me it was too late. The charger is having a problem where you need to wiggle it to get it to charge the laptop but it has no visible damage on the outside. It also behaved weirdly after I plugged it into my laptop (which by the way acted normally and started charging with this malfunctioning charger) ; the LED light on the magsafe stayed on after I unplugged it from my laptop but was a dim green as if there was a short inside the plug that was making it think it was still on. I fully charged my battery at home and everything is fine just worried if I had done damage to my laptop and if there are any procedures to check if it is damaged.