Got told I was using my multimeter wrong for 5 years

So last month at the hangar in Miami, my lead walks over and watches me trace a short on a 737 nav unit. He just says "you're putting the test leads on backwards." I've been doing it this way since I started avionics 3 years ago and never had a problem. But I tried it his way and the reading was way cleaner. Anybody else get told they've been doing some basic thing wrong for years?

3 comments

3 Comments

jordan4641mo ago

I get why swapping leads feels like a hack but I disagree that it's just a lazy shortcut. I've been in avionics for a bit and leaving your leads standard red-positive black-negative is about building a mental habit that sticks when things get hairy. You start swapping them around for one test and next thing you know you're on a live 737 bus and your brain defaults to wrong polarity. The clean reading might be real but consistency in your process matters just as much when you're up against a deadline.

rodriguez.cora3mo ago

18 years in automotive electrical and I always put red on positive because that's just how you do it in cars. Last year a guy from the radar shop showed me swapping them on a transistor test gives you the forward voltage drop without flipping the dial. I felt like a total idiot but it actually makes perfect sense now.

logan_white593mo ago

@rodriguez.cora I feel your pain man (or woman, sorry). Had a similar moment with my Fluke 87V - been testing diodes 'wrong' for years until a senior guy showed me the same trick. Felt like a caveman discovering fire.