signs of a bad logic board

[Eric]

Hi: I am wondering what are he signs of a defective logic board. My 
power adapter went dead. A local mac shop offered to lend me one until 
a new one came in (it would take a few days and I am in the middle of a 
project). The tech was checking out my book and told me I also needed a 
new logic board b/c my battery was not charging.  Actually, my battery 
is charging.  It charges when the computer is shut down, asleep and in 
use. (He had told me he couldn't a see the "charging sign - the bolt).  
I am under warranty so don't see why he would be trying to make this 
up.   Are there any other sings of a bad logic board I might be missing 
as since he has to order the new power adapter he could do the logic 
board at the same time.   this is a 667 dvi bought in august. thank 
you. eric

and it's an apple certified shop that has been around a while.