Tried dielectric grease on cannon plugs, nearly had a bad day

Last month I was doing a bench test on a nav unit and figured I'd be proactive, put a thin layer of dielectric grease on the pins of a 25 pin cannon plug before mating it. Worked fine for about 20 minutes then the display started flickering and the unit kept dropping the signal. Turns out the grease trapped some moisture and created a weird intermittent short across two pins. Had to pull it apart, clean every pin with contact cleaner and a brush, took like an hour. Now I only use it on the outer shell or rubber seal, never on the pins themselves. Anyone else had this bite them or am I just the lucky one?

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walker.andrew18d ago

Three blown fuses and a fried GPS antenna later, I learned the exact same lesson on a 26 pin plug in my boat last summer. I thought I was being smart too, slathered that stuff on like butter on toast. Turns out the grease just held the salt spray in place and turned the whole connector into a little battery. Spent four hours with a toothbrush and a can of DeoxIT while my buddy watched and laughed at me. Now I keep the grease for the rubber boot and the pins stay dry, lesson learned the hard way.