The battery icon indicates when it's plugged in, but it doesn't charge EXCEPT when it's in sleep mode or turned off. My battery and power supply tested good with other machines. I replaced the DC board and reset the PMU, but still no dice.
I had the same problem with my 12" powerbook, and the 3rd party repair shop reinstalled the OS when they put in a new hard drive. It doesn't make sense to me, but it seems to have fixed the problem.