My G4 AGP Graphics server appears to be dead for some reason. I reset the Energy Saver panel to auto shut down and start up and, well, the shutting down part worked just fine. Now it won't start up, though it powers on and the l.b. LED is lit, disks are spinning.... I have reset the logic board several discreet times over a 10 day period, with long periods without any power, as detailed in the Service manual and as described in some old posts from eQuill, replaced the RAM, reseated cards, etc. — all to no avail.

I am assuming that the power manager "computer" in the computer is defunct. So I am wondering, if a replacement logic board must be had, could I pop in a Gigabit Ethernet logic board instead of an AGP Graphics? The processors, RAM, etc. are compatible. Is everything else?