Here's a wire wrapped PDP10 backplane. You'd see something similar inside a PDP8 and the earlier PDP11s. https://upload.wikimedia.org/wikipedia/commons/f/f7/PD

Here's a wire wrapped PDP10 backplane. You'd see something similar inside a PDP8 and the earlier PDP11s. https://upload.wikimedia.org/wikipedia/commons/f/f7/PDP-10_1090_Backplane.jpg https://upload.wikimedia.org/wikipedia/commons/f/f7/PDP-10_1... Can you imagine trying to fault-find this with just a schematic, a meter, and a scope?