iBook G3 600 Dead?

Hi,

My old iBook will not start up, I was wondering if anyone had some ideas.
Specs: 640MB RAM, CDROM drive.

Here's the story:

Hard locked the other day, on restart get x'ed out circle instead of apple logo.
Here's what its doing now:

• Chimes on startup but will not boot off cd; Flashing ?/finder logo,

• will not boot into firewire target mode; black screen, then shuts off(!)

• Reset PRAM, NVRAM, PMU, no change.

• Replaced Hard Drive with a good used one I had lying around, no change.

• WILL boot into open firmware.

Is the logic board hosed? Or is there something else I can try.

Thanks,

Jay