I've been working with an Early '08 Core2Duo White MacBook that a very good friend gave to me a week ago. It would only work with the power cord as the battery in it was original and, I'm sure, long dead. Got a new battery for it a few days ago and ran it through a few charge/discharge cycles and all seemed well. Never worked with a MacBook before, so I thought that the connector's light going from bright green or orange to the dim green was a power saving feature.
Tonight, after having it plugged in for a couple hours, I looked and the battery was showing a low percentage of charge for as long as it had been connected. I wiped both connectors with isopropyl and began to go through XnriquX's procedure but was stopped when on connecting the charger the laptop wasn't getting power. Dim green light but wouldn't start up.
On inspecting the cable connector I could make out that one of the pins in the center had slid down into the plastic housing. A few taps on the table and there it was out again. I played with it for a while connected to the MacBook to see if rocking the connector a little would work. (During this I saw the connector's dim light go from its usually steady green to a dim green/orange flashing of short duration. This happened twice.) I finally got a steady bright green light and was able to power up. I installed the battery, connected the charger and again got a bright green that switched to a bright orange for about 30-45 seconds and went to dim green. I checked both System Profiler > Power and System Preferences > Energy Saver and both are telling me the battery is charging with this steady dim green light. Just did a quick check and still charging, with a dim green light. Looks like a "mostly hit, sometimes miss" situation until I decide to replace the charger. Curiouser and curiouser.
Thanks for the great web site and all the sharing that goes on here. Its enabled me to get to know my new MacBook with its various problems and just as varied solutions from the knowledgeable folks here. I also appreciate all of the guides that are available here. I know I'll have to go inside the MacBook to see if I can cure the optical drive of its inability to eject a disc. Cheers