Click a net label to trace it, with endpoints colour-coded input · output · in/out. Click an IC box (either panel) to select it in both, click again to deselect (multi-select OK), Esc clears all. Use the IC rail on the far left to jump straight to a chip. A net name shown muted like this and prefixed $ is one I coined for a node the 1985 drawing leaves unlabelled; every other name was read off the drawing. Hover a pin for its net's story.
Interboard connectors (the band cables between the boards). The circled letter+number labels on the drawing are connector row + pin
edge: 24/b speaker out, 25/c +12V in (also feeds the 2/8 coin counters), 26/d 12V return
