I replaced the two 100 microfarad, 6V capacitors on the logic board and voila! everything was good again. The bottom line was that the computer was locking up during the bootup sequence when it tried to wake up the Ethernet card. Those two caps are obviously crucial in supporting communications with the PDS slot. As uniserver and others have pointed out, it's best to replace ALL the caps on an old Macintosh before even trying to debug a hardware problem. I have to admit to getting sidetracked since the symptoms matched a condition someone else had attributed to a hard drive problem and the board did not show any signs of cap leakage. I could have isolated the problem earlier, but was not diligent enough to document what I had/had not done in the first place, i.e. verified operation with/without the Ethernet card. Finally, I need to apologize for my earlier rant at uniserver. I wasn't that frustrated, but it's difficult to sense attitude in emails and I didn't appreciate what I felt were disparaging comments. I really do appreciate all the help that you folks provide on this site; I couldn't have fixed either my SE/30 or the LC 575 without it. :b&w:
