A story about Magic (Jargon File)

None of that should be affected when the switch is flipped, that's the bit I'm struggling with. Sure, connecting a wire somewhere could act as an antenna but attaching a switch to the unconnected end of the antenna can't do anything. It's very weird.

> The switch could be connecting ground trace to the casing

This seems most likely - that there's actually a conductive path on one side of the switch from the switch body to the metal frame it's bolted to, so flipping it does take the frame in and out of circuit (doing something like changing capacitance or introducing RF noise on the ground plane which something in the PDP is sensitive to.)

If the wire went to signal ground and the case was at electrical-power-outlet ground then flipping it could pull the signal-ground pin up/down to electrical-power-outlet ground, which in this case was enough to cause a reset/reboot.

Or Lucas Electric were involved and it had a negative ground.

No come to think of it if Lucas Electric were involved it wouldn't have booted in the first place.