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Troubleshooting wire

By James Gengler, Alaska

As an avionics technician I am often found troubleshooting wiring for opens or shorts. On one occasion I was troubleshooting a fifty foot run of 22 gauge twisted/shielded pair for a direct short to ground. Using a Fluke 189 Digital Multimeter I traced the short between the center conductor and the shield about half way down the wire where the wire had been inadvertently pinched. The result of the short was the malfunction of the aircraft's complete flight display system. Because of the 189 accuracy measurements, the moving of the wire would change the measurement indication on the meter, displaying a high impedance short. As a result a lengthy troubleshooting problem was made quite simple.