http://docs.info.apple.com/article.html?artnum=50959 may be a start. In your case particularly try numbers 6 and 8. 7 may apply, but I'm assuming you don't even hear a chime at all in which case you won't be able to do that anyway. 3 could be a possibility unless you're certain of the type of power adapter it needed.

Beyond that it's probably something physically broken or burned out that has to do with the power connection (right near where the adapter plugs into the PowerBook).