Chose a DMM with a microamp range over my old Fluke for troubleshooting

Been working avionics for about 8 years now and always used my trusty Fluke 87V for everything. Last week I had this weird ghost issue on a King KX 165 nav radio where the display would flicker but only sometimes. My buddy Mike from the shop next door told me to try a meter that can read microamps since these older radios draw tiny current on the backup circuits. I picked up a Brymen BM869s for around $170 and man it caught a 3.2 microamp drop on a corroded pin that my Fluke just couldn't see. Turned a 3 hour headache into a 20 minute fix. Anyone else run into a situation where a different meter saved you time on a tricky fault?

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2 Comments

alexj994mo ago

Man that's a great catch, microamps really show stuff you'd never see otherwise.

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evah404mo ago

I used a Fluke 87V on a old power supply board once, set to microamps and found a 2.5µA leak I missed with regular DC mode. Turned out to be a cracked ceramic cap near a voltage regulator that looked totally fine otherwise. Swapping that part saved the whole board from slowly dying over time.

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