Found a quick way to check for bad coax connectors on the bench

Was chasing a weird intermittent fault on a nav system for a Cessna 172. The signal would drop out, but only sometimes. I got tired of pulling the whole unit and re-running the cable. So I grabbed a multimeter, set it to the continuity beep, and touched the center pin to the outer shield on the connector end I had off. If it beeped even a little, the connector was junk. Found three bad ones in about ten minutes that way. Saved me a whole afternoon of guesswork. Anyone else have a fast bench check for coax before you put it back in the plane?

2 comments

2 Comments

umam9517d ago

That continuity check is a bit too simple though (it might miss a high-resistance short). A proper insulation resistance test with a megger is what the manual would call for, honestly.

charlesb8917d ago

I saw a guy at the shop last month burn up a control board because the megger test voltage was too high. The manual might call for it, but you have to check the specs for the electronics first. A low voltage insulation tester is safer for modern gear. That high resistance short is a real problem, but so is frying a $500 part with a 1000V test.