I've looked all over the internet for answers to this problem and haven't been able to find a solution. I have a 2006 core duo 17" macbook pro, out of warranty. Recently the magsafe adapter stopped working, I assumed it was because the magsafe adapter started to fray (nothing new as I've gone through two already). Took it to the apple store and bought a new one (with L connector) since they wouldn't replace it outside warranty. Came back, still wouldn't charge/recognize the magsafe until I realized that the magsafe would only be recognized if plugged in while computer was off or asleep and then turned on. If the computer is on, and running on battery power and then I plug it in, the magsafe will not light up and not be recognized by the os. I looked it up, couldn't find any specific information but found information about resetting the pmu and smc. I've tried this multiple times, 5 seconds, 50 seconds, etc. Every combination and it doesn't fix the problem. It's not a huge issue, I just have to make sure the macbook is asleep or off before i plug it in. I even tried reinstalling snow leopard. Anyone have any ideas? I'd like to keep the machine alive and it's working despite the inconvenience mentioned above. My question(s), is there any way to fix this? if not, is this a dangerous problem. It could be the battery I suppose. It's at 369 cycles but still holds a charge (90%), and appears as normal under system profiler. I honestly have no clue.