The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Day: December 9, 2011

  • Digital Voltmeter Fuse Gotcha

    Measuring some low-value resistances with  one of my DVMs produced weird results: dead shorts around 10 Ω.

    Differential diagnosis:

    • Test lead tips clean
    • Wires firmly mounted in probes
    • Banana plugs OK
    • Short banana jumper across jacks reads 10+ Ω

    Took the meter apart and what do we see? An ABC ceramic fuse in good old PCB clips:

    DVM fuse holder
    DVM fuse holder

    Spinning the fuse dropped the resistance by a few ohms. Adding a minute drop of DeoxIT to each end, rotating the fuse to scrub it in, and wiping off the excess put the total resistance back around 0.2 Ω where it should be.