Pulled a beat-up King nav/com from a junkyard plane last month for a side project. Turns out someone had jumpered the audio lines wrong, which explained the weird static. Got it cleaned up and working on my test bench with a basic signal generator. Felt pretty cool to bring a piece of history back to life. Now I'm hunting for a cheap scope to make these fixes easier.
I was working on a plane where the altitude encoder kept showing random numbers. I thought about swapping it out but checked the ground wires first. Turns out, the shield wire had come loose at the connector. I just tightened it back up and the readings went back to normal right away. This quick check stopped me from ordering a new part and wasting a whole day. Now I make it a habit to look at grounds before anything else on these jobs. It's a small thing that really helps keep things moving.