I've been using my 17" MacBook Pro for about two months in what I call "limp" mode. It no longer charges batteries, and if I try to use it with the screen turned up to full brightness, it will shut down (by just turning off instantly) if I try to do anything that taxes the processor. It will work with my bus-powered USB external hard drive, but not if I turn up the brightness on the screen or do any really significant processing, like opening multiple photos in RAW format at one time, etc.
I'm thinking about changing the magsafe cable, but I can't imagine that is the real problem. The symptoms started happening when I had drained my battery, and when it was still warm, I plugged the computer in. As soon as it started charging, I turned it on, and as soon as it had booted up, I moved the computer across the table toward me. The magsafe cable pulled out, because I didn't have enough slack in the cable. Before it turned off on me, I quickly plugged it back in, and it didn't seem to light up all the way. This had happened once before, and unplugging it and plugging it back in seemed to fix it, so that is what I did this time. That little light on the magsafe connector has never worked at full brightness again. It's as if I'm using my airline power adapter. (You know, that one that looks like it would plug into a cigarette lighter plug in your car.)
The light on the magsafe connector still comes on, but only very dimly. I've tried other power adapters, thinking it was just my adapter or magnetic connector, but the one at the Apple store that I tried (was working with the 17" MacBook Pro on display) did not work any better than mine. I'm sure the problem is in the computer.
I don't see the magsafe board available to buy here. Does anyone have any ideas or know anything about my situation?