Hickok 534 with Added Options

This is a Hickok 534 that I repaired and calibrated for a Customer. The Customer asked me to wire a Bias fuse bulb and test points for checking plate current.

The Hickok 534 has a built in multi-tester with VOM capability. This model has a common failure in the multi-tester circuit that switches the meter from tube testing to multi-meter testing that causes the meter to not operate when testing tubes.

The plate current test points have a precision resistor so a millivolt meter can be installed to measure the voltage across the resistor that is proportional to the current in the plate circuit. A current meter is not required to measure the plate current and a jumper is not required to test tubes when not measuring plate current.

It is a good idea to install a Bias fuse bulb in tube testers that don’t have a fuse bulb. Over current through the Bias pot can cause damage and there are no replacements available for the custom wire wound Bias pot.

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2 thoughts on “Hickok 534 with Added Options”

  1. David Holder says:

    Just curious how you got the surface so shiny. And…do you repair and calibrate Jackson 648? If so, how much? Thank you!

  2. DLandon says:

    I didn’t do any cleaning of the deck. It came to me from the Customer looking like that. Contact me through the contact form and we can discuss your Jackson 648.

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