• EEVblog #544 – Fluke 5450A Resistance Calibrator Teardown

    What’s inside a vintage Fluke 5450A Resistance Calibrator used in cal labs to calibrate multimeters?
    Schematic HERE
    Coto reed relay
    High Resistance measurement with a relay matrix:

    Forum HERE

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      • Johm

        One really gets astonished in his 20’s that not many years ago electronics was as simple as 7400 or 4000 series series and a few ‘of the shelf’ components; double/single sided boards and thru-hole technology. Added to that a complete 200 page Service Manual with Theory and Operation and schematic and everything! It’s just like this resistance calibrator, you could mod it by yourself at home! Today you buy a mobile phone and you can’t even take apart the cover, I’d like a bit of the old days… (the days of pornographic PCB’s)

      • Trav

        I recognized the Potter and Brumfield name right away. Very well known in the US. Although to be honest, I always saw their name in the bowling alleys as AMF/Potter-Brumfield. In 1954 PB was bought by AMF, a large name for their bowling pin-spotting equipment.

        A great reference. http://www.fundinguniverse.com/company-histories/potter-brumfield-inc-history/

        • Trav

          Also, in 1985 P&B was sold to Siemens in Germany.

          • https://twitter.com/bgumcasting bubblegum casting

            really? I had no idea!

      • Jonas Wissting

        After comparing a Fluke 341A (cal in 1987), 2 PREMA 5000 (cal in…well…???), a Solartron 7065 and a (new) Agilent 34461 it is the Agilent that differs most (well within spec thou).
        I’d rather trust the old fluke.

      • John Dowdell

        Sprague are under the Vishay umbrella now.

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