Hickok 539C Tube Tester with Enhancements

This is my current go-to-tester. I acquired this tube tester from a Customer and it has been calibrated and several enhancements added. This is a very clean tube tester and doesn’t show much wear at all. The case has a few scuffs, but is overall in great shape.

I converted the tube rectifiers to solid state, and added a Bias fuse holder for the #49 fuse bulb. Converting to solid state rectifiers affects the calibration and some circuit modifications have to be made to accommodate the lower filament load on the transformer. The #83 tube is getting harder to find and is getting expensive. Converting to solid state rectifiers cuts down the filament load on the transformer and the heat generated. This will help extend the life of the transformer and the tube tester.

I recommend adding a Bias fuse bulb to any tube tester that does not have it installed originally. This protects the bias pot if the bias current gets too high. The Bias pot is no longer made and there is no replacement available.

Several enhancements have been made to this tube tester to enhance the accuracy. I do these enhancements when I calibrate a 539 tube tester.

The meters in this tube tester are original and are all within specifications.

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4 thoughts on “Hickok 539C Tube Tester with Enhancements”

  1. stephen says:

    Would using the Hickok 539C with a step down 110V transformer help extend the life? Just in-case, what do you charge for these SS conversion enhancements and calibration? Thank you,

  2. Dean Turnbull says:

    Hi just wondering if this is for sale pls?

  3. DLandon says:

    Not really. The best bet is to keep the line voltage at or below the line set voltage at all times.

  4. DLandon says:


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