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.

Month: July 2012

  • AMP 842448-2 HF PCB Filters: Still Alive

    A vial in the bottom of Mad Phil’s EMI Go-Kit contained a handful of these doodads:

    AMP 842448-2 HF PCB Filters
    AMP 842448-2 HF PCB Filters

    The label on the vial came from AMP with a handwritten 842448-2. Searching on the obvious terms eventually produced a Surface Mount EMI Filters catalog from Spectrum Control, with page 25 saying that it’s a 10 A DC ferrite pi filter with a 20 dB insertion loss over 100 MHz; evidently, SC bought AMP’s product line and is keeping it alive for all the Mil-Spec folks. Oddly, you can’t find that catalog using the site’s built-in search function with the part number.

    Rather than keep an entire catalog of parts I’ll never have, I used pdftk to snip out and rename the page for later reference:

    pdftk surfacemountcatalog.pdf cat 25 output "AMP 842448-2 HF PCB Filter.pdf"

    After it reaches the Internet, it never goes away…

  • Jacking Up The Microscope

    Microscope with machinists jack
    Microscope with machinists jack

    The stereo zoom microscope over the electronics bench lives on the end of long support arm that tends to be just slightly wobbly. Part of the problem is that the far end is anchored on the sponge-backed laminate flooring I put atop the bench, but it’d be slightly wobbly even with a firm base on the plywood bench top.

    So I prop up the microscope with a machinist’s jack and it’s all stable & good.

    This one happens to be from an ancient Starret 190 set that I accumulated along with some other tooling, but any of the cheap imitations would work just as well.

    The two bubble level vials help get the microscope axis exactly perpendicular to the bench surface, which makes the difference between good overall focus and a blurred image with a single line in focus. Here the jack is vertical and the microscope is tilted slightly toward the edge of the bench; the jack has a pivot below its knurled top plate.

  • Garden Dragonfly Ornament: Eye Re-Repair

    Alas, urethane glue didn’t hold the eye marbles in the garden dragonfly ornament for very long. Although the cured glue had a wonderfully smooth surface where it contacted the balls and it had plenty of contact area, that wasn’t enough.

    This time, I used acrylic caulk that should stay gummy enough to maintain a good grip:

    Garden Dragonfly ornament - re-reglued eye marbles
    Garden Dragonfly ornament – re-reglued eye marbles

    The next step, I suppose, will be to drill a hole in each ball for a stud and epoxy the things in place…