The massive toroidal transformer inside the sub clicked . The blue LED around the input jack, dead for six years, flickered. Then held steady.
Leo spent three nights tracing continuity on a dead control pod. He found it: Pin 9 wasn’t “NC” (Not Connected) as the public diagram claimed. It was SDA —Serial Data. Pin 14 was the clock. They had hidden a miniature I²C network inside the audio cable. logitech z5500 wiring diagram exclusive