Unpopular opinion: old school analog test gear is better than digital for finding intermittent faults

Was talking to a retired avionics guy named Pete at the hangar last Tuesday. He said when he worked on F-16s in the 80s, he'd use a Simpson 260 meter to chase down glitches in the wire bundles. Told me digital stuff filters out the noise you actually need to see. I've been thinking about that all week with a PFD that keeps dropping out in turbulence, analog meter showed a bad ground pin in 10 minutes that my Fluke missed after 3 hours. What do you guys use for intermittent stuff, old school or all digital?

2 comments

2 Comments

holly_flores7926d ago

Buddy of mine runs a repair shop for old motorcycles, swears by his old Tek scope from the 70s. He had this one bike that would die randomly when it rained, digital multimeter showed nothing wrong. Hooked up that analog scope, watched the trace wiggle just a hair when he sprayed water near the ignition module, turned out to be a cracked solder joint that only showed up with moisture. That Fluke is a great tool for steady readings, but when you need to see a signal dance around in real time, nothing beats watching a needle bounce or a trace flicker. I still grab my old Simpson for the weird stuff, just feels like you're fighting with the actual gremlins instead of trusting a screen.

jamesblack26d ago

Yeah that moisture trick is the real deal. I keep an old Heathkit scope on the bench just for that. The digital ones will average out a glitch so fast you never see it happen. Had a CNC machine at a shop that would lose position only when the coolant pump kicked on. Digital meter showed nothing. Old Simpson VOM showed the ground reference jumping around by half a volt. Chased it to a corroded terminal block behind the panel. Drove a screwdriver through the insulation on the wire to prove it then replaced the whole section. Saved three days of swapping boards.