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.

      • Trav

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

        • 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.