2 64NIC+ boards arrived on April 20, and I assembled one in the evening. Initial testing with Devia’s NIC-Test was unsuccessful, so I gave up for the night. After work on the 21st, I pored over the schematics and determined I had miscopied a resistor layout from Eric Pratt’s 64NIC design. The resistor must be tied to ground, not Vcc. Dubious that such a small change would make the board work, I nonetheless made the change and …. it did nothing.
I decided I’d ruined one board, so I assembled the second board, taking care to make the resistor mod before plugging it in. Devia’s NIC-Test worked immediately. Later, I tried the apparently ruined board and it also worked, so it appears I did not completely ruin the board.
Given the success, I immediately released the board to production that evening.