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Found a trick for tracing intermittent ground faults in the panel

I spent 3 hours last week chasing a ground fault on a King KX 155 nav radio that kept popping up and disappearing... driving me nuts. Finally tried hooking up a 12V test light in series with the ground lead instead of just using my multimeter. The light flickered dimly when I wiggled the harness near the backshell connector. Turns out a single strand of shielding was barely touching the pin inside the connector. Fixed it in 10 minutes after that. Has anyone else used a test light this way or do you guys stick to megger testing for intermittent stuff?
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2 Comments
gavine41
gavine411mo ago
Last year I had a similar ghost fault on a Garmin GNS 430. My multimeter showed nothing solid. I ended up clipping a small 28V bulb between the ground pin and airframe. The bulb glowed just enough to see when I bent the wire bundle coming out of the tray. Found a cracked solder joint inside the connector that only made contact sometimes.
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wyatt771
wyatt7711mo ago
Ever try using a headlamp as a poor man's wiggle test light?
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