I recently acquired a MacBook 1,1 2Ghz unit. I purchased a new battery for it. The machine was running flawlessly while plugged into the power adapter, and better still with the new battery plugged in. As soon as the battery was fully charged, the MacBook began randomly shutting down. Sometimes it took a couple minutes, other times it took mere seconds.

I looked around the forums and did a few searches online. I've read about the "random shutdown syndrome," and I don't think my case is quite similar. I've already updated my SMC to the most current firmware. When the MacBook is unplugged and has the battery installed, the MacBook will begin to boot and shut off, or on occasion, will completely boot and then shut off. The unit doesn't seem to be overheating, nor are any wires exposed on the inside causing a false heat reading.

My cycle count on the battery is still showing "1" and it has a healthy charge level, as any new MacBook battery should.

If anyone else has had this issue, or a similar one, please chime in. I appreciate your expertise.